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Full text of "Qualitative organic analysis; an elementary course in the identification of organic compounds"

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CHEM BLDG 



QUALITATIVE 

ORGANIC ANALYSIS 



QUALITATIVE 

ORGANIC ANALYSIS 



An Elementary Course in the 
Identification of Organic Compounds 



BY 

OLIVER KAMM 

Director of Chemical Research, Parke, Davis & Co. 

Formerly Assistant Professor of Chemistry, 

the University of Illinois 






NEW YORK • 

JOHN WILEY & SONS, Inc. 

London: CHAPMAN & HALL, Ijmited 
1923 



K2 



Copyright, 192ie 
By OLIVER KAMM 



PRESS OF 
1 BRAUNWORTH & CO. 

4/25 BOOK MANUFACTURERS 

BROOKLYN, N. Y. 






PREFACE 



The teaching of Qualitative Organic Analysis Is gradually- 
receiving recognition as an important factor in the training of 
the chemist. In 1905, the subject was taught in only two or 
three universities; ten years later courses were offered in from 
fifteen to twenty of the leading schools in this country; and in 
1918 the subject was prescribed for all colleges undertaking the 
training of chemists under the supervision of the United States 
Government. Only the armistice prevented the institution of 
this sweeping innovation in chemical curricula. 

Qualitative Organic Analysis has not been taught generally 
because of the assumption on the part of chemists that the multi- 
plicity of organic compounds excludes the possibility of a sys- 
tematic procedure. This is the opinion of those who have not 
taught the subject; those who have had experience in presenting 
the work both in the classroom and the laboratory realize that 
Qualitative Organic Analysis is capable of logical and systematic 
treatment and that it is of fundamental importance in the elemen- 
tary training of the chemist in the organic field. 

The course here outlined is essentially that offered by the 
writer at the University of Ilhnois in 1920. The basis for its 
claim to systematization is outlined in Chapters I and 11. The 
most radical individual departure from other analytical schemes 
consists in the subdivision of organic compounds into seven 
solubility groups and the application of this classification to a 
systematic procedure. 

The chemist to whom most credit is due for the development 
of organic qualitative analysis is Professor S. P. MuUiken. The 
appearance of his exhaustive reference book on the "Identifica- 
tion of Pure Organic Compounds," Vol. I, in 1905 is obviously 
the beginning of this line of work. The authors of foreign texts 

iii 

1 14-lS 



\ 



iv PREFACE 



on the subject have curiously avoided crediting the pioneer in 
the field. The present writer extends such recognition with 
pleasure. He wishes also to offer hearty acknowledgment to hii 
teacher and colleague, Dr. C. G. Derick, at whose suggestion the 
presentation of this text was undertaken. The procedure here 
outlined is based upon a course offered by Dr. Derick in 1908 
and subsequently developed with his constant sympathetic help 
and encouragement during the years 1911-1915. 

The course outlined in this text is intended to follow the 
usual work in synthetic organic preparations; Part A corre- 
sponds to the classroom work, while Part B embodies the actual 
laboratory directions. The steps required in the identification 
of an unknown are outlined in Chapter VI and are treated in 
more detail in the subsequent chapters in the order in which 
they are required in an actual identification. The work is usually 
apportioned as follows for a one-semester course of sixteen weeks, 
covering thirty-two laboratory periods of three hours each. 

Solubility Tests on Known Compounds, 

Chapter VIII. One week. 

Classification Reactions on Known Compounds, 

Chapter IX. Five weeks. 

Identification of Six or Eight Individual Compounds, 

Chapters VI -XI. Six weeks. 

Examination of Mixtures, 

Chapter XII. Four weeks. 

In certain branches of stud}'', and particularly in Chemical 
Engineering, the schedule will not permit instruction in Qualita- 
tive Organic Analysis as a separate course. In such classes it 
has been found best, nevertheless, to present an abbreviated six 
or eight weeks' course in place of the latter part of the second 
semester's work in organic synthesis. Such an abbreviated course 
should consist of the solubility work of Chapter VIII, selections 
from Chapter IX so as to require only about three weeks' work, 
and the identification of about four individual compounds. 

The classified tables in Part C have not previously been used 
in actual laboratory instruction and suggestions in regard to cor- 
rections and additions from those who have occasion to use them 
in classwork will be appreciated. The tables are intended only 
for preliminary aid before resorting to the advanced reference 
books. Formulas and specific instructions for the choice of deriva- 



PREFACE V 

lives are omitted for pedagogical reasons; the former are usually 
superfluous and the latter should be a part of the student's own 
work based upon the principles discussed in Chapter X. 

The writer takes this opportunity to acknowledge his indebt- 
edness not only to the extensive works by Mulhken, but also to 
the authors of two smaller but nevertheless very valuable manuals 
that have from time to time been used as text-books in his courses, 
namely: Clarke's "Handbook of Organic Analysis" and Noyes 
and MuUiken's "Laboratory Experiments on the Class Reac- 
tions of Organic Substances (1897)." He also wishes to express 
his gratitude to Dr. C. S. Marvel, who has read the manuscript 
and offered other valuable assistance, to Dr. E. A. Wildman, 
who has read the proof, and to Mr. A. O. Matthews, who has 
prepared the drawings. 

Oliver Kamm. 
Detroit, Michigan 
October, 1922. 



CONTENTS 



PAGE 

A. Theoretical Part 

I. The Method of QuaUtative Organic Analysis 1 

II. The SolubiUty Behavior of Organic Compounds 8 

III. Classification Reactions : Hydrocarbons and Their Oxygen and 

Halogen Derivatives 29 

IV. Classification Reactions: The Simple Nitrogen and Sulfur 

Compounds 59 

V. Classification Reactions: Compounds with Unlike Subs tituents 81 

B. Laboratory Directions 

VI. Procedure for the Analysis of an Individual Compound 107 

VII. Determination of Physical Constants and Analysis for the 

Elements Ill 

VIII. Laboratory Work on the Solubility Behavior of Organic 

Compounds 126 

IX. Laboratory Work on Classification Reactions of Organic 

Compounds 132 

X. Preparation of Derivatives 148 

XI. Quantitative Analysis of Substituent Groups 167 

XII. Examination of Mixtures 176 

C. Classified Tables of Compounds 187 

Index 241 



^ 



oTthT 



QUALITATIVE ORGANIC ANALYSIS 



PART A 



CHAPTER I 
THE METHOD OF QUALITATIVE ORGANIC ANALYSIS 

The multiplicity of organic compounds, the instability of 
many of the individual members when compared with the more 
common inorganic compounds, and the relative complexity of 
mixtures of organic substances (particularly many of the mix- 
tures obtained from natural products) make organic analysis 
appear difficult to the uninitiated. Inorganic analysis, on the 
other hand, appears simple and systematic because we have too 
arbitrarily limited it more or less to a method for the analysis 
of the commoner ions; no scheme has yet been proposed for a 
complete and systematic method for the analysis of inorganic 
co?npounds. 

In the present procedure for qualitative organic analysis no 
attempt is made to outline for organic chemistry that which has 
not yet been accomplished in the older inorganic field; it is 
intended as an elementary introductory course to form a ground- 
work for the more specialized lines of advanced organic analysis, 
many of which still lie mainly in the realm of research. 

In discussing the procedure for the identification of an 
organic compound, it is well for us to differentiate between 
(a) the method of characterizing new organic compounds which 



2 QUALITATIVE ORGANIC ANALYSIS 

have not been described previously and (6) the more rapid method 
that may be apphed to those compounds which have already 
been subjected to characterization. It will be found, however, 
that the qualitative procedure often will be applicable even to 
the identification of compounds not yet described in the litera- 
ture. 

THE CHARACTERIZATION OF AN ORGANIC COMPOUND 

When a new compound is prepared in the laboratory or when a 
new individual is isolated from some natural source, extensive 
work is often required for the complete assignment of its struc- 
ture; i.e., for the characterization of the compound. The usual 
steps in the procedure for the assignment of structure to both 
organic and inorganic compounds are as follows: 

(1) Isolation and Purification, 

(2) Qualitative Analysis, 

(3) Quantitative Analysis, 

(4) Molecular Weight Determination. 

These four steps are often sufficient for the characterization of 
an inorganic compound; on the other hand, organic compounds 
almost invariably require a fifth consideration: 

(5) Assignment of Structure According to the Atomic 

Linking Theory, 

(a) Analytical Method of Structure Proof, 
(6) Synthetical Method of Structure Proof. 

The importance of the last step may be illustrated best by a 
specific example, A definite chemical individual is isolated from 
a natural product. Qualitative analysis demonstrates the pres- 
ence of carbon, hydrogen, and oxygen. Quantitative analysis 
shows these three elements to be present in the proportions 

2C : 4H : 10. 

The formula for the compound can therefore be written (C2H40)z. 
Molecular weight deteiminations demonstrate the value of x to 



METHOD OF QUALITATIVE ORGANIC ANALYSIS 3 

be three ; the correct molecular formula can now be adopted as 
C6H12O3. A glance at the literature shows, however, that this 
formula represents the true composition of about eighty organic 
compounds; obviously then these compounds possess different 
internal structures and it is necessary to ask the question, 
" How are the atoms arranged within the molecule?" It is 
by answering this question that we can differentiate between 
these various isomers, and this answer is obtained by applying 
in the aid of the Atomic Linking Theory the analytical and 
synthetical methods for structure proof. 

If the procedure outlined above were the one actually used 
in a laboratory course in qualitative organic analysis, the iden- 
tification of an organic compound would be a very difficult and 
laborious task indeed. It is fortunate, therefore, that a simpler 
method is at hand. 

In connection with the identification of an organic compound, 
time will usually not permit a quantitative analysis for the ele- 
ments (step three, above), since it is desired to identify a com- 
pound not in a few days' time, but during a few hours. For the 
same reason, molecular weight determinations are applied only 
in exceptional instances. Step five, the assignment of structure, 
often involves years of investigational work. Fortunately, this 
work has already been accomplished for an enormous number of 
organic compounds, and the path has thus been cleared in the 
direction of qualitative identification when these compounds are 
again met. 

THE METHOD OF SUPERPOSITION 

A given unknown organic compound is said to be identical 
with a known when the two compounds agree perfectly in all of 
their physical and chemical properties. Such a method is of 
course impractical, and actual laboratory experience teaches us 
that agreement between several of the physical properties 
together with uniformity of the chemical reactions of the two 
compounds,^ justifies us in assuming complete agreement in all 
properties either physical or chemical. 

"■This implies also that the products of the reactions (derivatives) must 
agree iu their physical constants. 



4 QUALITATIVE ORGANIC ANALYSIS 

The method of superposition Hes at the basis of any scheme of 
identification, but because of the multiplicity of organic com- 
pounds this method in itself would prove of little value; a scheme 
of analysis dependent upon it alone would lead to an immense 
amount of unnecessary work without the equivalent return in 
development of logical thinking and without the accumulation of 
a systematic knowledge of organic chemistry which may be best 
developed in the qualitative field. In order to be of value, the 
method of superposition must be preceded by a systematic 
method of elimination. 



THE METHOD OF QUALITATIVE ORGANIC ANALYSIS 

The steps to be taken in the rapid identification of a compound 
which has previously been characterized are as follows : 

1. Purification of the compound and determination of the 

most common physical constants, 

2. Qualitative analysis for the elements, 

3. Determination of solubility behavior, 

4. Application of class reactions to those types indicated 

by tests 1, 2, and 3, 

5. Use of the literature on known classes of compounds, 

6. Preparation of derivatives and determination of physi- 

cal constants of these derivatives. 

The systematic method for the identification consists in 
locating first not the individual compound but the class or prefer- 
ably the homologous series to which the compound belongs. 

Let the student be given an unknown organic compound, 
which may be any one from among thousands of known com- 
pounds. Obviously, it would be a waste of time to search 
through the literature in order to find constants and reactions of 
known compounds which check with the physical and chemical 
properties of the unknown. We shall seek first the " class " 
to which the unknown belongs. The determination of its melt- 
ing- or boiling-point will exclude certain classes of compounds; 
the qualitative analysis for the elements (C, H, N, S, X, etc.), 
will further limit the possible classes, and after the apphcation 



METHOD OF QUALITATIVE ORGANIC ANALYSIS 5 

of the prescribed solubility tests the possibihties will be still more 
limited. Furthermore, the " class reactions," the so-called 
homologous tests, will limit the number of classes to very few, 
and preferably to only one. At this stage, but not before, may the 
literature be consulted. The position of the compound within a 
given class will then be determined by means of its physical 
constants, and to prove absolutely that the process of reasoning 
is correct, as well as to differentiate between several possible 
individuals, one or more derivatives are prepared and identified 
by means of their physical constants. 



THE THEORETICAL BASIS FOR QUALITATIVE ORGANIC 

ANALYSIS 

The Value of Homology. — In the procedure for qualitative 
identification of an unknown, as sketched above, systematization 
is possible because of the occurrence of homology. Fortunately, 
nature has divided the immense number of organic compounds 
into certain definite series called homologous series. In an homo- 
logous series a given member differs from the preceding or succeed- 
ing member by the constant difference, CH2. For example, in 
the homologous series comprising the monobasic paraffin acids, 
we have as the first five members: 

HCO2H Formic acid, 

CH3CO2H Acetic acid, 

CH3CH2CO2H Propionic acid, 

CH3CH2CH2CO2H Butyric acid, 

CH3CH2CH2CH2CO2H Valeric acid, etc. 

From a scientific standpoint, the existence of homology is of 
fundamental importance for two reasons : (1) The chemical prop- 
erties of every member of an homologous series are the same; 
they differ only in the speed of reaction, not in the kind of reaction. 
(2) The physical properties of the members of a given homologous 
series are different. For example, in the above homologous series 
we note in each member the presence of a carboxyl group together 
with a saturated radical, hence each acid must possess the chemical 
properties of these two radicals, i.e., must possess the same chemi- 



6 



QUALITATIVE ORGANIC ANALYSIS 



cal properties. (We note, however, that in the above series, the 
first member possesses a carboxyl group united to a hydrogen 
atom and we may expect therefore a variation in certain chemical 
properties.) On the other hand, each member of a given homo- 
logous series may be differentiated from any other member by 
means of physical properties. 

TABLE I 









Sp. gr. 

25°/25° 


M.p. 

of 

p-tolui- 

dide 


M.p. 
of 


Duclaux 


Name 


M.p. 


B.p. 


p-nitro- 
benzyl 


con- 
stant 












ester 




Formic acid 


+ 8° 


101° 


1.291 


.52° 


31° 


4 


Acetic acid 


+ 15° 


118° 


1.051 


153° 


78° 


7 


Propionic acid .... 


-22° 


141° 


0.991 


123° 


31° 


11 


n-Butj'iic acid .... 


- 8° 


162° 


0.956 


74° 


35° 


18 


Isobutyric acid .... 


- 5° 


155° 


0.946 


109° 


liquid 


25 


n-Valeric acid 


-58° 


185° 


0.937 


70° 




28 



The homologous series to which the unknown compound 
belongs must be determined mainly by means of the chemical 
reactions characteristic of its groups and then its physical prop- 
erties will reveal the position of the compound in the homologous 
series. The principle of homology has been kept in mind in 
outlining the method of analysis given above. In actual prac- 
tice, it is found more convenient to consider classes of organic 
compounds in place of homologous series. In some instances 
these classes may be identical with given homologous series, 
whereas in other cases a class may comprise members from several 
homologous series; for instance, under primary aromatic amines 
we shall classify aniline, «-naphthyl amine, o-anisidine, p-amino- 
acetophenone, etc. Although each one of these four individuals 
belongs to a different homologous series, they all exhibit analo- 
gous chemical reactions in respect to the amine group. 

In the subsequent laboratory work, we shall seek to apply the 
systematic procedure outlined above under " The Method of 
Qualitative Organic Analysis." 



METHOD OF QUALITATIVE ORGANIC ANALYSIS 



REFERENCES 

The following books are suggested for reference in connection 
with the study of Qualitative Organic Analysis: Mulliken: The 
Identification of Pure Organic Compounds, Vols. I, II, and III.^ 
Rosenthaler: Nachweis Organischen Verbindungen. Clarke: 
Handbook of Organic Analysis. Weyl: Methoden der Organ- 
ischen Chemie. Allen : Commercial Organic Analysis. Sherman : 
Organic Analysis (Foods). 

The student, from his previous training in organic chemistry, is expected 
to be familiar with reference books such as Richter's Lexicon and Beilstein's 
Handbuch, and he should cultivate a familiarity with Chemical Abstracts 
as a source for the more recent work. 

1 Volume IV of MuUiken's work will be available in 1923. 



CHAPTER II 

THE SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 

Physical Properties and Molecular Structure. — The atomic 
hnking theory attempts to explain the physical and chemical 
properties of organic compounds by means of the linking together 
of atoms. In applying the theory for the prediction of the physi- 
cal properties of organic compounds, the following considera- 
tions are of fundamental significance: 

(a) The kind and number of atoms present (chemical 

composition), 
(6) The mode of linking of the atoms (constitution), 
(c) The spatial arrangement of the atoms (configuration). 

In any systematic method for the identification of organic 
compounds, both physical and chemical properties are utilized 
for locating the class, or, preferably, the homologous series to 
which the unknown belongs, and subsequently specific physical 
tests are applied to locate the individual within the series. 
Unfortunately for organic analysis, the study of the relationship 
between physical properties and molecular structure is still a 
relatively undeveloped field, certainly so when viewed from the 
standpoint of potential possibilities. 

In the present chapter, we shall discuss in an elementary 
manner the relation to molecular structure of only one physical 
property, that of solubility. This topic is chosen because it lies 
at the basis of the present scheme of analysis. The discussion 
is intended for the beginner; the experienced analyst is able to 
utilize efficiently generalizations based upon other physical prop- 
erties as well. 

Prediction of Solubility. — From the atomic linking structure 
of an organic compound, we may with fair assurance predict in 

8 



SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 9 

a qualitative way its solubility behavior. For the purposes of 
qualitative organic analysis we may reverse this procedure, and 
from the results of solubility tests draw certain inferences con- 
cerning the nature of a given unknown ; these will depend upon the 
results of an elementary analysis of the compound as well as upon 
its physical constants. It is for this reason that qualitative 
analysis for the elements and ■ a determination of the physical 
constants should precede conclusions drawn from the solubility 
behavior of a given compound. 

Arbitrary Classification of Solvents. — In discussing the sol- 
ubility behavior of organic compounds, we shall for convenience 
place the solvents used in two groups: 

(a) Inert solvents, 
(6) Reaction solvents. 

This division, we shall find, is not altogether sharp. Under Inert 
Solvents we shall arbitrarily group those solvents, like water, 
ether, alcohol, benzene, etc., which may be predicted to exert their 
solubility effects because of a structural relationship to the sub- 
stance dissolved. 

Under Reaction Solvents we shall group those solvents which 
cause solubility because of a chemical reaction of the kind ordi- 
narily expressed by equations; viz., the neutralization of an acid 
by a base with the production of a soluble salt. The fact that 
solubility in water may produce ionization or hydrolysis in certain 
cases and solvation in general is recognized, but nevertheless an 
arbitrary distinction of this kind will prove of value in the sub- 
sequent discussion. 

RULES FOR THE PREDICTION OF SOLUBILITIES IN THE 
INERT SOLVENTS 

For the prediction of the solubihties of organic compounds in 
the Inert Solvents we shall have occasion to apply four fairly 
general rules: 

I. A substance is most soluble in that solvent which is 
most closely related structurally to the solute. 
II. As we go higher in a given homologous series, the 
members become more and more, in their physical 



10 QUALITATIVE ORGANIC ANALYSIS 

properties, like the hydrocarbons from which they 
may be considered as being derived. 

III. Compounds of very high molecular weight, such as 

highly polymerized compounds, exhibit decreased 
solubility in the inert solvents. 

IV. The solubility behavior of solid compounds is depend- 

ent upon the molecular aggregation in the solid 
state. 

The four solubility rules have been presented in the order 
given for the reason that in the prediction of the solubility behavior 
of a known compound they will be used in this order. Knowing 
the formula for a given compound, we proceed first to predict its 
solubility in a special solvent on the basis of relationship in struc- 
ture between the solute and the solvent. (Rule I.) Next, we 
must consider the effect of position within the homologous series 
(Rule II) and for this purpose we must be able to predict, of course, 
the solubility behavior of the hydrocarbons. Finally, we must 
consider possible limitations imposed by the two qualifying Rules 
III and IV. 

Discussion of the Rules of Solubility. — Rule I. A substance 
is most soluble in that solvent which is most closely related structur- 
ally to the solute. This rule will receive verification from the ele- 
mentary applications that will be presented throughout this 
chapter. Hexane is insoluble in water (1 : 1000), which is in 
accordance with what we should expect from the dissimilarity 
in structure between hydrocarbons and water. On the other 
hand, hexane dissolves in three parts of methyl alcohol, while in 
ethyl alcohol it is soluble in all proportions; ethyl alcohol is closely 
enough related to hexane in structure to produce miscibility. 
Naturally we shall not hesitate, therefore, to predict that hexane 
will dissolve in all proportions in a very intimately related sol- 
vent, octane; in fact, such a mixture will give rise to what the 
physical chemist terms " an ideal solution '' since it obeys the same 
laws that ordinarily apply only to extremely dilute solutions. 

Although ethyl alcohol and hexane dissolve in all proportions 
and although this relationship holds for many of the homologues 
not only of the series C„H2^ + 2 but also for the series C„H.„, C„H2„_6, 
etc., we find that paraffin hydrocarbons of sufficiently high molec- 
ular weight are not completely miscible in ethyl alcohol; for 



SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 11 

example, ordinary kerosene requires several volumes of ethyl 
alcohol for complete solution. This behavior is covered by Rule 
III. Although kerosene is not completely miscible in ethyl alco- 
hol, we may predict, according to Rule I, that it will dissolve 
more readily in an alcohol of higher molecular weight (butyl 
alcohol), which is more closely related to kerosene in composition. 
Actual experiment verifies this prediction. 

A few additional specific examples dealing with some common 
organic compounds will be presented here to illustrate the apph- 
cation of Rule I. 



TABLE II 

Solubility of p-Dibromobenzene in Various Solvents at 50° 



Solvent 


Grams 

solute per 

100 grams 

of saturated 

solution 


Solvent 


Grams 

solute per 

100 grams 

of saturated 

solution 


HOH 


0.0 
20 
26 
27 
30 




67 


CH3OH 


CSj 


72 


CH3CH2OH 


C6H6 


71 


CH3CH2CH2OH 

(CH3)2CHCH20H 


CeHsBr 


54 







The effect of substitution in organic compounds by halogen 
usually results in decreased solubility in the inert solvents; the 
effect of halogen is therefore analogous to an increase in number 
of carbon atoms. p-Dibromobenzene is insoluble in water, but is 
extremely soluble in a solvent like benzene which is closely related 
in structure to the solute. The alcohols lie intermediate in struc- 
true between water and the hydrocarbon solvents, and this cor- 
responding effect is reflected in the data of Table II. Ether is 
still more closely related to the hydrocarbons and the above 
solubility value is such as might be predicted qualitatively. The 
solubility of p-dibromobenzene is less in bromobenzene than in 
an equal weight of benzene, but this irregularity is removed when 
solubility is expressed in grams of solute per mole of solvent. 



12 



QUALITATIVE ORGANIC ANALYSIS 



TABLE III 
Solubility of Naphthalene in Various Solvents at 20' 



Solvent 


Grams 
naphthalene 

per 

100 grams 

solvent 


Solvent 


Grams 

naphthalene 

per 

100 grams 

solvent 


HOH 


0.003 

8.2 

9.8 
14,0 
13.0 
23 


CH.,CH2CH2C02H 

(CH3)2CHCH2C02H .... 
CHCI3 


22 


CH3OH 


17 


CHiCH^OH 


31 


CH3CH2CH2CH2CH2CH,, 
CHaCO^H 


CS2 


36 




36 


CH^CILCG?!! 




28 









Problem 1. — Interpret the data in Table III in accordance with pre- 
dictions based upon Rule I. Why would the solubility of naphthalene in 
mono-hydroxy alcohols up to Ce be predicted to lie below 14 g. per 100 g. 
solvent? Given the solubility in acetic acid, do the solubilities in propionic, 
butyric and valeric acids agree with predictions? Why would one expect 
naphthalene to be less soluble in toluene than in benzene? Predict qualita- 
tively the solubility of naphthalene in the solvents formic acid, heptanoic 
acid, ethyl benzene, etc. Compare the solubiUties in hydrocarbons of the 
two series C„H2„+2 and CnRin-e, where n = Q. Do the facts agree with pre- 
dictions? Predict qualitatively the solubility of naphthalene in ethyl acetate. 

Prediction of solubility in the inert solvents such as carbon disulfide, 
carbon tetrachloride, chloroform, etc., is somewhat more difficult. In these 
instances it is sometimes convenient to consult the following table of dielectric 
constants. No definite relationship between dielectric constants and solu- 
bilities has been developed since unknown factors are involved; nevertheless, 
the dielectric constants may be used where they do not conflict with the more 
basic generalization given in Rule I. 

TABLE IV 

Dielectric Constants of Some Organic Solvents at 18° to 20° 



Water 81 

Methyl alcohol 32 

Ethyl alcohol 26 

Propyl alcohol 22 

Isobutyl alcohol 19 

Isoamyl alcohol 16 

Ethyl bromide 10 

Acetic acid 9.7 



Ethyl acetate 6.5 

Bromobenzene 5.2 

Chloroform 5.2 

Ethyl ether 4.4 

Carbon disulfide 2.6 

Benzene 2.3 

Carbon tetrachloride. . . 2 . 25 

Hexane 2,0 



SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 13 

According to Rule I, we may predict that naphthalene will dissolve to a 
limited extent in either ethyl alcohol or glacial acetic acid. A selection of the 
most efficient of these two solvents would be difficult without actual experi- 
ment. The dielectric values, however, indicate that acetic acid will prove 
superior. Explain. On the other hand, benzene and hexane differ only 
slightly in dielectric constants. Since benzene is very much more closely 
related in structure to naphthalene than is hexane, we find that the solubility 
of naphthalene is considerably greater in the former solvent: Rule I takes 
precedence over predictions based upon dielectric constants. 

Problem 2. — Look up in Seidell, "Solubilities of Inorganic and Organic 
Compounds," 1919, p. 136, the solubihty of benzoic acid in various organic 
solvents. Compare these values with the corresponding dielectric constants. 

Although the two common solvents, chloroform and carbon tetrachloride, 
are very closely related in composition, the table of dielectric constants 
suggests considerable variation in the solvent powers of these two com- 
pounds, which prediction is in agreement with actual experience. In many 
instances, chloroform exhibits an unusual solvent power. This is especially 
noticeable in the solubilities of some of the well-known alkaloids, such as 
atropine, quinine, cinchonine, quinidine, and hyoscyamine. 

The Second Rule of Solubility. — As we go higher in a given 
homologous series, the members become more and more, in their 
physical properties, like the hydrocarbons from which they may be 
considered as being derived. It should be noted that this statement 
is very broad in its apphcation; it refers to physical properties 
in general, whereas in our discussion we require only a limited 
application to one physical property, that of solubihty in the 
inert solvents. 

Figure 1 illustrates the application of the rule to the solu- 
bility in water of the aliphatic mono-hydroxy alcohols and mono- 
carboxyhc acids. Beyond the members possessing five carbon 
atoms the solubilities of the oxygenated derivatives rapidly 
approach those of the hydrocarbons. 

Many other illustrations of Rule II, together with numerical 
data, will be discussed in the latter part of this chapter in con- 
nection with the development of the solubility table. 

The Third Rule of Solubihty. — Compounds of very high molec- 
ular weight exhibit decreased solubility in the inert solvents. This 
is true even when the solvent and the solute are in the same 
homologous series, provided that there is sufficient difference in 
molecular weight. For example, low-boiling ligroin will not dis- 
solve solid paraffin in all proportions. Similarly, acetic acid will 
dissolve stearic acid only to the extent of about 5 per cent at 20°. 



14 



QUALITATIVE ORGANIC ANALYSIS 



The formula C6H12O6 immediately suggests a sugar very soluble 
in water, but (CeHioOs)^ may represent a water-insoluble sub- 

stance like cellulose. CH2O and CH3-C — H represent com- 
pounds extremely soluble in water, whereas (CH20)j; and 

(CH3-C— H)3 represent substances of limited solubility in water. 







Solubility Curve 








of 








Acida 
Alcohols 








Hydroca 


trbons 








.50 










1 


■ 40 










5 

3 


-30 


Alcohols 5^ \ 






PU 


20 


v\ 


— Acids 




10 


\\ 

Hydrocarbons N^ 


V 



3 4 5 6 

Number of Carbon Atoms 

Fig. 1. 



From the reaction between an amine and an organic acid we may 
isolate an amide of normal solubility. When, however, a dia- 
mine, such as p-phenylene diamine or benzidine, reacts with a 
dicarboxylic acid, the primary reaction-product may react again 
and again to yield finally substances of very high molecular weight. 
Such products are insoluble in the inert solvents. Many other 
analogous instances might be cited. Among the substances of 
high molecular weight we must make allowance, however, for 



SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 15 

certain types that yield colloidal solutions; this is especially 
noticeable with certain starches, proteins, and dyes. 

The Fourth Rule of Solubility.— The solubility behavior of solid 
compounds is dependent upon the molecular aggregation in the solid 
state. It is because of this factor that the solubility behavior of 
liquid compounds may be predicted more safely than that of 
solids. Solubility is dependent upon the species in equilibrium 
with the saturated solution. The molecular aggregation in the 
solid state finds expression, however, in other physical properties; 
for example, in the melting-points of the compounds. By judi- 
cious use of relationships which have been pointed out in this 
field, we possess a means of predicting many cases of solubility 
that might otherwise be treated as exceptions. 

Among compounds of a given homologous series, high 
melting-points^ may often be associated with low solubility. 
Among isomeric substances (space isomerism) the isomer least 
stable toward rearrangement possesses the lowest melting-point 
and the greatest solubility. Among position-isomers, such as 
the isomeric di- and tri-substitution products of benzene, only 
a fair agreement is found, with the assumption that the solu- 
bilities of the isomers are in the order of their melting- 
points .^ 

The melting-point and solubility relationships of the saturated 
aliphatic dicarboxylic acids illustrate this rule (IV) among com- 
pounds that are not isomeric but homologous. In this series, we 
must apply Rule II separately to the acids with odd and to those 
with even numbers of carbon atoms. Beyond the C7 member, 
we find, however, that one group is rapidly approaching the solu- 
bility of the other and both groups are rapidly approaching the 
solubilities of the corresponding hydrocarbons. (See Fig. 2.) 

In agreement with Rule IV, we find that the solubility of an 
organic compound is greater when the saturated solution is in 
equilibrium with the liquid substance than when in contact with 
the solid at the same temperature. For example, at 70° benzoic 
acid is soluble in water to the extent of 2 per cent provided that 
the saturated solution is in contact with solid benzoic acid; when 

1 This does not apply to compounds of the "salt type." 

2Carnelley and Tomson, J. Chem. Soc. 53, 791 (1888); 73, 618 (1898); 

J. prakt. Chem. 52, 72 (1895); 59, 30-45 (1899); J. Chem. Soc. Abstracts 92, 

i, 745 (1907). 



16 



QUALITATIVE ORGANIC ANALYSIS 



in contact with liquid benzoic acid the solubihty is three times 
as large. 

Physical Constants of Dicarboxylic Acids 



.2 e 



-189 




\ 2 ^^'° 




V 1/ I <i^^ A 


140° 




r\"\\\ 


A/"' 


1 1 ' V 1 


/ o 108° 
'l05 


/ 1 1 "°1 




' "- 


Solubility Curve 

]Vf P r„rva 


* 1 — 1 — 1 — 1 — 1 — 


^vO.lSg 0.25g o.lOg 

H V ? ^ 



3 4 5 6 7 8 

NuuLber of Carbon Atoms 

Fig. 2. 



A number of other well-known examples will now be considered. 
Among geometrical isomers (cis-trans type) we find that the most 
fusible isomer possesses also the greatest solubility. (See Table V.) 

A case analogous with the above is that dealing with the vari- 
ous isomeric cinnamic acids. The ordinary stable isomer (m. p. 
133°) is soluble ''n water at 25° to the extent of about one part 
in 15,000 while the labile acids (m. p. 68°, 58°, 42°) are soluble 
in about 100 parts of water. 

Among optical isomers, dextro and laevo enantiomorphs pos- 
sess identical melting-points and identical solubilities. The race- 
mic form usually differs in melting-point and in solubility. Among 



SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 17 

this class of compounds we find many examples illustrating the 
fact that solubility depends upon the molecular complexity of 
the solid. The tartaric acids furnish a typical illustration. 

In solution, the racemic tartaric acid may be represented as 
CO2H -(011011)2 -00211, as is indicated by its cryoscopic depres- 
sion and its ionization constant; its solubility is controlled, 
however, by the molecular complexity of the soUd. (See Table VI.) 

TABLE V 



Substance 




M. p. 


Solubility in 100 grams 
solvent at 20°. 




Water 


Ethanol 


CH— CO2H 

II maleic acid 

CH— CO2H 

HC— CO2H 

II fumaric acid 

CO2H— CH 


130° 
286° subl. 


60 g. 
0.6g. 


51 g. 
5g. 


TABLE VI 




M. p. 


Solubility in 

100 g. water 

(20°) 


Solubility in 
100 g. alcohol 

(25°) 


C4H6O6 d-tartaric acid 


170° 
170° 


139 g. 
139 g. 
20.6 g. 


27 g. 

27 g. 

2g. 


C^HeOs Z-tartaric aicd 


(C4H606-H20)2 '//-tartaric acid. . . 
(racemic) 




205-200° 



Among the di- substituted benzene derivatives, we find very 
often that the order of solubility lies in the order of the melting- 
points. This is illustrated in the solubilities of the following sub- 
stituted benzoic acids. 



18 



QUALITATIVE ORGANIC ANALYSIS 
TABLE VII 



Name of acid 


Melting-point 
of acids 


Solubility in 1000 

grams of water 

at about 25° 




Ortho 


Meta 


Para 


Ortho 


Meta 


Para 


Chlorobenzoic 


142° 


158° 


243° 


2.25 


0.45 


0.09 


Bromobenzoic 


150° 


155° 


254° 


1.86 


0.40 


0.056 


lodobenzoic 


162° 


186° 


265° 


0.95 


0.12 


0.027 


Toluic 


104° 


110° 


179° 


1.18 


0.98 


0.35 


Phthalic 


230° 


300° 


Subl. 


10. 


0.13 


0.0 


Nitrobenzoic 


147° 


141° 


238° 


r7.4~| 

2.5 
13. 4j 


3.4 


0.3 


Hydroxybenzoic 


158° 


200° 


213° 


10.8 


6.5 


Aminobenzoic 


144° 


174° 


187° 


5.6 


3.1 



In comparing the meta and para compounds in Table VII, it 
will be noticed that the higher-melting isomers are also the less 
soluble in water. This rule cannot at present be made more 
general so as to include also the ortho isomers because a number 
of well-known exceptions exist; these exceptions are indicated in 
the table by the brackets. It appears probable, however, that 
this irregularity is mainly disposed of in a solvent like benzene, 
which is more closely related in structure to the solute. See 
Table VIII. 

TABLE VIII 



Name of compound 


Me 


Iting-point 


Per cent solubility at 
20° in benzene 




Ortho 


Meta 


Para 


Ortho 


Meta 


Para 


Hydroxybenzoic 

Nitrobenzoic 

Nitrophenol 


158° 

147° 

44° 

118° 

69° 

32° 

38° 


200° 

141° 

95° 

90° 

112° 

44° 
53° 


210° 
238° 
114° 
173° 

148° 

82° 
124° 


0.8 
0.4 
50. 
5.7 

23 

70 
60 


0.01 
1.0 
1.5 
39 

2.5 

48 
35 


0.004 

0.03 

0.5 


Dinitrobenzene 

Nitraniline 

Chloronitrobenzene 

Bromonitrobenzene 


2 5 

ro.6 

12. 
29 
5 



SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 19 



SOLUBILITY IN THE REACTION SOLVENTS 

For the purpose of classification, we shall find cold concen- 
trated sulfuric acid an extremely valuable reagent; its main use 
consists in the subdivision of the group of compounds which we 
shall call the indifferents, i.e., compounds insoluble in water and 
containing neither acidic nor basic groups. We shall find that 
the saturated hydrocarbons (aliphatic and aromatic) are insoluble 
in this reagent under the conditions of the experiment and this 
holds true with but few exceptions chiefly among the tertiary 
members, for the halogen derivatives of these hydrocarbons. 
The oxygenated derivatives of these compounds (alcohols, 
ketones, esters, ethers, aldehydes, etc.) are almost invariably ex- 
tremely soluble (occasionally with decomposition) in this solvent. 

Cold concentrated sulfuric acid differs from the usual inert 
solvents mainly in that it forms a more stable addition product 
with the solute. The use of sulfuric acid in this solubility work 
is based not upon the usual sulfonation reactions but upon the 
formation of addition products from which the organic compound 
may usually be recovered unchanged. For example, ethyl ben- 
zoate will dissolve in all proportions in cold concentrated sulfuric 
acid to produce addition products ^ of the types 

[C6H5C02C2H5-H2S04] and [(C6H5C02C2H5)2-H2S04]. 

The ethyl benzoate may be recovered by pouring the acid solution 
into ice-water. 

Basic Groups. — Compounds possessing basic groups will react 
with dilute hydrochloric acid to produce water-soluble hydro- 
chlorides. Obviously, the degree of basicity of the amine group, 
the concentration of the acid used, and the solubilities of the amine 
salts are important factors, and these will be discussed in more 
detail in connection with the laboratory instructions. 

By far the most common basic groups are the amino and 
certain substituted amino groups. Sulfonium hydroxides, certain 
oximes, pyrones and their naturally-occurring derivatives (the 
anthocyanins), represent basic compounds which need consider- 
ation only in more advanced work. 

1 J. Kendall, J. Am. Chem. Soc. 36, 2498 (1914). 



20 



QU^&ATIVE ORGANIC ANALYSIS 



When an organic consMknd contains the group NH2, it is not 
necessarily basic in natui^ in fact it may be basic, neutral, or 
even acidic, the structure of that part of the molecule united to 
the NH2 group exerting the controlling influence. When a hydro- 
gen of ammonia is substituted by an alkyl or related radical, we 
obtain a primary amine which compares favorably with ammonia 
in basicity. 



TABLE IX 



Ammonia. . . 
Ethyl amine . 
Benzyl amine 
Allvl amine. . 



Ionization* 
constant K^° 



1.8 XlO-5 
5.6 XIO-" 
1.95X10-5 
4.6 XlO-5 



Diethyl amine. . 
Dimethyl amine 
Triethyl amine. 
Piperidine 



Ionization* 
constant K^' 



1. 26X10-' 
5.35X10-* 
5.9 XlO-5 
1.2 XlO-» 



* Scudder: Conductivity and Ionization Constants of Organic Compounds (1914). The 
values are only apparent ionization constants for the reason that only, a fraction of the 
amine is present as an ammonium compound. Cf. also Bredig, Zeit. Phys. Chem. 13, 
289-326 (1894). 

When the second and third hydrogens of ammonia are replaced 
by alkyl radicals, we find that the resulting secondary and tertiary 
amines are of approximately the same order of basicity as the 
primary amines. (See second column of Table IX.) 

If in place of alkyl or related radicals we introduce into 
ammonia an aryl radical, we note a tremendous drop in the ioniza- 
tion constant (Table X) to about one-millionth of its previous 
value. We may predict that a second radical, but of the alkyl 
type, will produce no further large change in basicity, but the 
introduction of a second aryl radical will produce a second large 
decrease in basicity, whereas a third aryl radical will produce a 
practically neutral substance. The phenomenon produced by two 
or three aryl groups may be accomplished by the introduction 
of a single radical of the acyl type. A second acyl radical will 
convert the nitrogen derivative into an acidic substance. That 
which is accomplished by means of two acyl groups may be called 
forth by a single group provided that the acyl group corresponds 
to a very strong acid (sulfonic acid). Examples of all of these 
cases are given in Table X. 



SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 21 



TABLE X 



Substance 



Ionization constant 



Reaction 



C6H5NH2 

CCH5NHCH3 

C6H5N(CH3)2.... 

(C6H5)2NH 

(C6HO3N 

C6H5CONH2.... 

CH3CONH2 

CH3CONHC6H5 

•CO- 
C6H4 p „ NH 

C6H5SO2NH2.... 



Kf° = 5 X 10-10 
^B° = 3 X 10-10 



A'b^° =0.3X10-1^ 
AS°°=4. 0X10-1^ 

A'i^°=5 XIO-^ 



Basic 

Basic 

Basic 

Almost neutral 

Neutral 

Practically neutral 

Practically neutral 

Practically neutral 

Acidic 

Acidic 



Among the basic compounds we shall find therefore primary 
(I), secondary (II), and tertiary (III) amines, provided that not 
more than one of the substituting radicals is an aryl radical. 
The nitrogen may be part of a ring structure, as in pyridine and its 

derivatives. The quaternary ammonium bases, (R)4==N — OH, 

are very strong bases like the inorganic hydroxides, but they are 
usually met in the form of their neutral salts. 

In addition to the basicity of the compound, we must con- 
sider also its solubility in water in order to predict its solubility 
in dilute aqueous hydrochloric acid. Amines of very high molec- 
ular weight occasionally possess such a slight solubility in water 
that they fail to dissolve in dilute acid. This instance is illus- 
trated by the following set of equilibria in which the reaction is 
shifted to the extreme left due to the insolubility of the free amine. 
Usually, however, the concentration of amine produced by hydrol- 
ysis is less than that which corresponds to its solubility in water, 
and therefore the amine is soluble in dilute acid. 



+H2O +HC1 

RNH2 ;=± RNH2 7 RNH3OH ^==3- RNH3CI 

(Solid) (Dissolved) — H2O — HCl (Dissolved) 



22 



QUALITATIVE ORGANIC ANALYSIS 



ACIDIC GROUPS 



Among the common acidic groups may be listed the following: 



Carboxyl. — C^O— H, 

Sulfonic, — S=0 

\0H, 



Phenol, Ar— O— H, 



Oxime, =N— O— H, 
Thiophenol, Ar— S— H, 

Enolic type, — C^C— H, 



C=0 C=0, 



Sulfone amide, — S==0 

\NHs 



OH O 

Imide, —C^ N— C^. 



I or II nitro 



-CH.-N< 



O 



-CHR— N 



^ 



O, 

o 



\ 



o. 



Compounds possessing these groups will in general dissolve in 
dilute NaOH solution since their sodium salts are soluble. The 
most common exception is to be found among those types which 
are very feebly acidic. When such members are also high in 
molecular weight, and therefore very sparingly soluble in water, 
we may observe insolubility in dilute aqueous alkali. 

Problem 3. — The sodium salt of a high molecular weight phenol was 
prepared by adding the calculated quantity of sodium ethylate to an alcoholic 
solution of the phenol. The sodium salt was filtered with suction and washed 
with water. When the compound was analyzed, sodium was found prac- 
tically absent. Write the equation (showing equilibria) to explain the 
reactions that took place when the salt was washed with water. 

Problem 4. — Write the enolic or "aci" formulas corresponding to the 
formulas given above for imides, I and II nitro compounds, sulfone amides, 
and enols. Note that all of the acidic groups may be considered as pos- 
sessing an hydroxyl group united to an unsaturated atom. 



SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 23 

The Solubility Table.— In order to use solubility data effect- 
ively in an elementary analytical procedure, it is found con- 
venient to group organic compounds into seven solubility groups. 
Table XI illustrates such a division. It will be noticed that only 
a limited number of solvents is used in this solubility plan; viz., 
water, ether, benzene, cold concentrated H2SO4, dilute HCl, and 
dilute NaOH. The use of a greater number of solvents would 
lead to a more cumbersome scheme with greater numbers of 
irregularities; we may, however, secure valuable additional infor- 
mation about any individual group from the use of special solvents. 

We shall now proceed to develop this solubility scheme and to 
place various common classes of compounds into the proper 
solubility groups. This is done not only to develop an ability to 
predict solubility behavior, but in order to emphasize the fact 
that this solubility table, which will be used later in the procedure 
for analysis, need not be an object of memory work. This table 
need not be overburdened with many classes of compounds of 
the " mixed type " where several unlike substituents are present; 
these types will call forth no special difficulties in the analytical 
procedure. 

To predict solubility we begin with a knowledge of the solu- 
bility behavior of hydrocarbons; the solubility of other classes 
of compounds will then be predicted according to the rules that 
have been discussed for both " Inert " and " Reaction " solvents. 
In the laboratory, methane, ethylene, and acetylene, were pre- 
pared and collected over water; long before taking up the study 
of chemistry we knew that gasolene and kerosene (mixtures of 
hydrocarbons) do not dissolve appreciably in water. In the 
laboratory, benzene was used for extractions from aqueous solu- 
tions partly because of its limited solubility in water. It is appar- 
ent, therefore, that the hydrocarbons (saturated paraffins, cyclo- 
paraffins, unsaturated aliphatics, olefines, and aromatics) are 
insoluble in water. ^ This is true also of the halogen substitution 
products of the hydrocarbons. Since these compounds contain 
neither acidic nor basic groups they are classified as indifferents, 

1 The hydrocarbons are insoluble for the purposes of this classification. 
Hexane is soluble in water only to the extent of 1 part in 1000 and the 
members higher in this homologous series decrease in solubility approxi- 
mately according to the rule 1 : ^ : | : ^. Compare this regularity with the 
solubilities of n-amyl, n-hexyl and n-octyl alcohols given in Table XTI. 



24 



QUALITATIVE ORGANIC ANALYSIS 



and since with few exceptions (pages 19 and 37), they are insoluble 
in cold concentrated H2SO4, we may conclude that the paraffin 
hydrocarbons, the aromatic hydrocarbons, and their stable halogen 
substitution products fall in Group VI . 

TABLE XI 

Solubility Table (General Plan) 



Water Soluble 



Group I 
Soluble ii 
Ether 



Group II 
Insoluble 
in Ether 
and Ben- 
zene 



B 

Water Insoluble 



Group III 
Soluble in 
dil. HCl 



Group IV 

Soluble in 
dil. KOH 



IndifFerents 



Hydrocarbons and their ox- 
ygen and halogen deriva- 
tives 



Group V 

Soluble in cold 

con. H2SO4 



Group VI 
Insoluble ii 
cold con 
H2SO4 



Other indif- 
ferents con- 
taining, N, S, 
etc. 



Group VII 



The most common oxygen substitution products of the hydro- 
carbons to be considered are the alcohols, aldehydes, ketones, 
acids, and esters. The solubility behavior of these derivatives 
may be predicted by applying Rules I and II. Solubility data 
for the mono-hydroxy alcohols in water is shown in Table XII. 

TABLE XII 



Alcohol 


Solubility in 100 
grams H2O at 20° 


Alcohol 


Solubility in 100 
grams H,0 at 20° 


Methyl 


00 
00 
00 
00 
10 
9 


Isoamyl 

n-Amyl 

n-Hexyl 

n-Heptyl 

n-Octyl 


2.5 


Ethyl 

Propyl 


1.5 
0.5 


Isopropyl 

Isobutyl 


0.03 


n-Butyl 









SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 25 

The lower members in this group of alcohols are closely related 
to the solvent (water), i.e., the hydroxyl group forms a large pro- 
portion of the weight of the molecule; the lower members in the 
above series are therefore predicted to be very soluble in water 
and facts agree with this prediction since the first four members 
are found to be soluble in water in all proportions. However, 
as we go higher in this homologous series, the compounds become 
more and more in their solubility behavior like the hydrocarbons 
from which they are derived (Rule II). The hydrocarbons are, 
however, insoluble in water and this is found to be true of alcohols 
of high molecular weight. For practical purposes, C.5 will be con- 
sidered as the dividing line; mono-hydroxy alcohols with fewer 
than five carbon atoms will be classified as water-soluble and those 
with more than five carbons will be grouped as water-insoluble. 
From analogy in structure to ether, we may predict that the alco- 
hols are soluble in ether. The alcohols of low molecular weight 
(Ci to C5) are placed, therefore, in Group I and those of high molec- 
ular weight (indifferents and soluble in H2SO4) are placed in 
Group V. 

Similar considerations hold for aldehydes, ketones, acids, and 
esters. 



R 

1 


R 

1 


R 

1 


R 


R 

1 


1 
C=0 


1 
C=0 


1 
C=0 


C=0 


1 



\ 


1 


\ 


\ 


1 


H 


R 


OH 


OR 


R 


Aldehyde 


Ketone 


Acid 


Ester 


Ether 



In the lower members, oxygen forms a considerable proportion of 
the weight of the molecule and the lower members (less than five 
carbon atoms) are quite soluble in water.^ The higher members, 
again, are found to approach the corresponding hydrocarbons in 
their solubility behavior; they are insoluble in water (Rule II) 
but are soluble in ether (Rule I). 

Aldehydes, ketones, monocarboxylic acids, and esters of low 
molecular weight (up to C4) are placed in Group I, while aldehydes, 

1 The effect of oxygen in producing water solubility in various aliphatic 
compounds lies in the order —C- — OH > C=0 > OH > C— O— C 



26 



QUALITATIVE ORGANIC ANALYSIS 



ketones, and esters of high molecular weight, being indifferent 
and soluble in sulfuric acid, are placed in Group V. The water- 
insoluble acids are placed, however, in Group IV. Why? 



TABLE XIII 



Solubility of Various Compounds in Water at About 20°-25° in Parts 

PER 100 



Number of 
Carbon Atoms 


Aldehyde 


Ketone 


Acid 


Ester 


Ci 


Miscible 
Miscible 
20 
Iso 11 
Normal 3.6 
1 




Miscible 

Miscible 

Miscible 

Iso 20 

Normal 00 

4 




C2 




Miscible 


Cs 

C4 
C5 


Miscible 
25 

4.0 


8 
2 



Diethyl ether is soluble in fifteen parts of water at 20°, but 
the ethers of higher molecular weight are less soluble (Rule II), 
and therefore fall in Group V. 

The mono-amino derivatives of the hydrocarbons are deriva- 
tives of a compound (ammonia) which is very soluble in water. 
The lower members in which the amino group represents a large 
part of the molecule, are expected therefore to be water-soluble. 
The higher members will resemble, however, the hydrocarbons 
(Rule II) ; they are found to be insoluble in water. The amines 
of low molecular weight (Ci to Co) must be classed in Group I, 
and those of high molecular weight in Group III because of the 
presence of the basic group. Among the aralkyl amines, 

ArC„H2„NH2, 



the benzene nucleus is equivalent in its solubility effect to about 
four aliphatic carbons. Benzyl amine although possessing seven 
carbon atoms is water-soluble. Among the branched chain com- 
pounds, two methyl side-chains are qualitatively equivalent in 
solubility effect to one chain-carbon atom. 



SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 27 

Problem 5. — Refer to the solubility data in Table XII and predict the 
approximate solubility in water of (a) benzyl alcohol and (6) amylene hydrate, 
CH3 
I 
CH3CH2 — C — OH. The observed values are (a) 3 to 4 parts per 100 and 

I 
CH3 

(6) 12 parts per 100. 

Problem 6. — Aniline, which possesses one CHo group less than benzyl 
amine, is soluble in water only to the extent of 1 part in 30. Explain this 
apparent anomaly. See also Tables IX and X. 

In the discussion of the effect of substituents upon the basicity 
of amines (page 20), we found that certain groups (acyl groups, 
a second aryl group, etc.) removed the basicity. Such compounds 
are often spoken of as " negatively substituted amines," and must 
be classified among the indifferents, and since they contain nitro- 
gen are placed in Group VII, irrespective of their behavior toward 
sulfuric acid. Amides of low molecular weight (R-C0-NII2, 
where R is Ci to 4) are water-soluble and sparingly soluble in the 
hydrocarbon solvents; they therefore fall mainly in Group II. 

It is to be noted that although solubility in ether or benzene 
is used to differentiate between Groups I and II, these solvents 
are not required for assigning any classes of compounds to the 
remaining five groups of the Table. Thus, certain compounds 
falling into Groups III or IV may be very soluble in ether, while 
other members are almost insoluble in ether. Similar variations 
are noticed especially in Group VII. These are facts of value to 
an experienced analyst but they do not affect the classification 
into the seven main groups; for further subdivision of these 
groups such solubility data might be utilized. 

The Effect of Polysubstitution in the Oxygenated Deriv- 
atives of the Hydrocarbons. — The mono-hydroxy and mono-car- 
boxy derivatives of the hydrocarbons are soluble in ether and in 
benzene. The presence of several hydroxyl or of several carboxyl 
groups will decrease solubility not only in benzene but also in 
ether. The compounds become more like water in structure and 
less like the hydrocarbons and ether. 

For example, propyl alcohol is miscible with ether and benzene 
in all proportions, but the presence of two or three hydroxyl 
groups causes a very low solubility in ether and insolubility in 
benzene. Such compounds will be placed in Group II. As we 



28 



QUALITATIVE ORGANIC ANALYSIS 
TABLE XIV 



Alcohols. 


Solubility in ether. 


Solubility in benzene 


CH3CH2CH2OH 


Miscible 

Slightly soluble (7%) 

Slightly soluble (3%) 

Insoluble 


Miscible 


CH3CHOH • CH2OH 


Almost insoluble 


CH2OHCH2 0112011 


Insoluble 


CH2OHCHOHCH2OH 


Insoluble 



go higher in a given homologous series Rule II must be applied. 
For example, the compound 

CH3CH2CH2CH2CH2CH2 • CHOH • CH2OH 

will be appreciably soluble in ether, despite the presence of two 
hydroxyl groups. 

The dicarboxylic acids are solid compounds the solubility 
behavior of which has received consideration in the discussion of 
Rule IV. 

The simple carbohydrates are rich in hydroxyl groups and are 
consequently very soluble in water but insoluble in ether. High 
molecular weight carbohydrates (CeHioOs)^, such as starches and 
cellulose, are insoluble in water as well as in ether. The insolu- 
bility of most starches in cold water is controlled also by the 
physical structure of the starch granules. In hot water, the 
external membranes of the cells are broken and a colloidal starch 
solution results. 

The presence of both hydroxyl and carboxyl groups in the 
same molecule, especially in low molecular weight compounds, 
tends to cause ether insolubility. In the absence of any unusual 
complexity in the solid state, there results great solubility in water; 
examples are glycolic, lactic, tartaric, malic, and citric acids, 
which therefore fall in Group II. This discussion applies also 
to low molecular weight amino acids where we note the additional 
effect of salt formation. Salts not only of this type but of organic 
acidic substances with inorganic bases and of organic bases with 
mineral acids, with only a limited number of exceptions, are 
insoluble in ether. 

Space will not permit the discussion of additional solubility 
data, but, in order to emphasize further the fact that the Solubility 
Table need not be treated as a piece of memory work, an addi- 
tional class exercise is assigned at the end of Chapter VIII. 



CHAPTER III 
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 

HYDROCARBONS AND THEIR OXYGEN AND HALOGEN 
DERIVATIVES 

The study of the elements of organic chemistry will have made 
familiar the characteristic reactions of the common classes of 
organic compounds, viz., the reactions of the carboxyl group, the 
carbonyl group, the hydroxyl group, the nitro group, the amine 
group, the aryl hydrocarbon group, etc. The following discus- 
sion, together with the experimental work in Chapter IX, will 
consist of a partial review of the facts that are furnished so plenti- 
fully in a general course in organic chemistry. This review will 
offer an opportunity for a reclassification of the information which 
is unfortunately too often first studied in a memorizing fashion. 
A systematic review from a different standpoint and a regrouping 
of this information for the purposes of qualitative analysis is of 
value as a general training for the chemist. 

Qualitative organic analysis is possible because of the facts 
of homology; all the members in a given homologous series 
exhibit the same kind of chemical reactions, but they differ in the 
velocity of reaction. Another important problem for considera- 
tion is the effect of a given atom or group of atoms in modifying 
the homologous tests of other groups simultaneously present in 
the molecule. It is one of the functions of qualitative analysis 
to teach some of this detailed information, particularly in connec- 
tion with the actual laboratory study. 

Most of the reactions to be discussed are adaptable to the 
differentiation between various classes of possibilities within a 
given solubility group; others possess value mainly in testing for 
a limited number of individual compounds; a third type is adapted 
mainly to quantitative work after a search has been limited to a 

29 



30 QUALITATIVE ORGANIC ANALYSIS 

certain class; and a fourth type is useful after the identification 
has been narrowed down to only a few individuals within a given 
class when standardized reactions are required for the prepara- 
tion of derivatives. 

Not only is a familiarity with the reactions of organic chemis- 
try required for the purposes of qualitative organic analysis, but 
it is important also to know the conditions under which reactions 
are applied and the limitations and interferences to which a test 
may be subject under any set of given experimental conditions. 
Such a knowledge must come primarily from the laboratory. 

Behavior of Hydrocarbons Toward Cold Concentrated Sul- 
furic Acid. — With the exception of the unsaturated members, 
the hydrocarbons and their halogen derivatives will be found in 
Solubility Group VI. Compounds of the define type will be 
placed in Group V, although they do not dissolve in cold concen- 
trated sulfuric acid readily, as is the case with oxygen derivatives 
of the hydrocarbons. Compounds of the ethylene series react 
with sulfuric acid in the following manner, the unsaturated carbon 
atoms showing a preference for the acid radical in the following 
order : Tertiary > secondary > primary. 

CH3\ CHsv 

>C=CH-CH3+HO-S02-OH -> >C-CH2-CH3 

CH3/ CH3/ I 

Isoamylene O-SO2OH 

An alkyl sulfuric acid 

The above reaction proceeds smoothly under suitable experi- 
mental conditions, viz., proper temperature control and acid 
concentration. The solution of alkyl sulfuric acid may be poured 
into water, neutralized with excess alkali, and the corresponding 
alcohol recovered by distillation. When an olefine is treated 
with concentrated sulfuric acid without special precautions, as 
in the usual solubility test, only a portion of the compound is 
converted into a soluble alkyl sulfuric acid, the remaining portion 
being polymerized to compounds of limited solubility in sulfuric 
acid. The first step in such a polymerization may be repre- 
sented thus: 

CH3\ H2SO4 CH3\ /CH3 



2 >C=CH2 > >CH-CH2CH=C< 

CH3/ CUs"^ \CH 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 31 

The mother substance, ethylene, is fau'ly resistant to polymeri- 
zation but its homologs, beginning with propylene, are more 
reactive. Amylene may be converted with 85 per cent sulfuric 
acid at 0° into an almost quantitative yield of the corresponding 
alkyl sulfuric acid but with less precaution it yields polymers con- 
taining ten, fifteen, and twenty carbon atoms. 

Problem 7. — When n-butyl alcohol is catalytically dehydrated it is con- 
verted mainly into a mixture of n-butene-l and 2-methylpropene-l. Write 
the equations to represent the reactions which take place when this gas 
mixture is absorbed in sulfuric acid under conditions that do not lead to 
polymerization. 

Although paraffin hydrocarbons do not dissolve in sulfuric 
acid, technical products such as petroleum ether, ligroin, gasolene, 
kerosene, etc., which are often represented in text-books as typical 
mixtures of paraffin hydrocarbons, exhibit considerable reaction 
with sulfuric acid, due mainly to the presence of unsaturated 
compounds. The amount of unsaturation in these technical 
products has increased greatly during recent years, with the advent 
of " cracking processes " for the production of lower-boiling frac- 
tions from petroleum. 

Aromatic hydrocarbons are insoluble in cold concentrated 
sulfuric acid under the conditions chosen for the solubility tests. 
A few individual members among the poly-methyl benzenes are 
sulfonated slowly by cold concentrated sulfuric acid but the reac- 
tion is not liable to be confused with the usual nonsulfonating 
solubility test. 

The Unsaturated Hydrocarbons. — Unsaturation in organic 
compounds may be detected by a variety of addition reactions. 
The addition of sulfuric acid to an ethylene double union has 
already been illustrated. Other reagents which may be added 
are halogens, halogen acids, ammonia and substituted ammonias, 
diazomethane, ozone, hypohalites, nitrosylchloride, hydrogen 
peroxide (H2O + O), tautomeric esters, organo-metallic com- 
pounds, hydrogen, etc. Some of these addition reactions are of 
great technical importance; others are of value in synthetical 
work, particularly in connection with the determination of 
structure of compounds. 

Only two of the above addition reactions are convenient and 
general enough for use in elementary qualitative work. These 
two reactions are: 



32 QUALITATIVE ORGANIC ANALYSIS 

(a) Addition of halogen, usually of bromine, and 

(6) Oxidation at the position of unsaturation by KMnO* 
solution. 

These reactions are typical not merely of unsaturated hydro- 
carbons but of unsaturated linkages in general. In the presence 
of certain negative groups, addition of bromine may be very slow 
but in such cases the permanganate test will be found sufficiently 
sensitive. Bromine may be decolorized, due to substitution 
reactions, particularly among the phenols, aromatic amines, enols, 
certain aldehydes, etc., but in such instances halogen acid may be 
detected as a by-product. The above-mentioned types will also 
respond to the permanganate test: these considerations are again 
studied in connection with the actual experimental work of 
Chapter IX. What inorganic compounds might be responsible 
for decolorization of bromine and permanganate? 

By means of bromine addition, we may differentiate the 
unsaturated hydrocarbons from the saturated types. 



CH. 



CH 



HC CH2 inCCk HCBr CH2 

I I + 2Br2 > I I 



CH2 CH2 CH2 CH2 

CH2 CH3 CHsBr CH3 

Terpene (dipentene) Tetrabromo addition product 

of dipentene 



CH3 

K 



in CCI4 
-f Br2 > No reaction under same conditions. 



CH3 CH3 

p-Methyl isopropyl 
benzene (cymene) 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 33 



Problem 8. — Write the formulas for the products obtained from (a) the 
addition of HBr to dipentene, (b) the addition of ozone to isoprene, (c) the 
action of bromine water upon ethylene. J. Chem. Soc, 111, 242 (1917). 

Bromine addition thus serves to differentiate between two 
main groups of hydrocarbons; the reaction is adaptable also to 
quantitative determinations (page 170) and as such is used exten- 
sively in quantitative analysis of certain classes of organic com- 
pounds. Only a few relatively unimportant hydrocarbons fail 
to respond to this test. On the other hand, among the unsatu- 
rated derivatives of hydrocarbons, there is considerable variation 
in the ease of reaction with bromine. 

TABLE XV 

Differentiation between Hydrocarbons 

Hydrocarbons +5 per cent Br2 in CCh at 0° to 20° 



Molecular* quantities of Br2 decolor- 
ized without production of a consid- 
erable quantity of HBr. 

Unsaturated hydrocarbons 



Ethylene type 



Acetylene type 



B 

No addition of Br2 in the cold and in 
diffused light. 

Hydrocarbons of saturated type 



Paraffins, insolu- 
ble in dimethyl 
sulfate. 

Not sulfonated by 

HoS04-S03 



Aromatics, solu- 
ble in dimethyl 
sulfate. 

Sulfonated b y 

H2S04-S03 



* From the boiling-point of an unknown of a given type, the approximate number of 
carbon atoms in the molecule may be predicted. 

A differentiation between the two subclasses Ai and A2 is 
seldom necessary since this is accomplished in connection with 
the final identification of the individual compounds. A triple 
union will usually add four atoms of bromine, but this is true also 
of the diolefines. When both hydrogens of acetylene are replaced 
by so-called negative groups (phenyl, carboxyl, etc.) only two atoms 
of bromine are added. Ethylene derivatives containing such 
negative groups add bromine rather slowly. (Example: Addi- 
tion of Br2 to cinnamic acid.) 

Oxidation with Potassium Permanganate. — The first effect of 
permanganate upon an ethylene union probably consists in the 



34 QUALITATIVE ORGANIC ANALYSIS 

formation of an oxide which usually is detected only in the form 
of its hydrolytic product. 



O 
R-CH=CH2 —^ 



R-CH— CH. 



H2O 
> R-CHOH-CH2OH 



The resulting glycol, as such, would be comparatively stable 
towards permanganate oxidation but, while in the process of 
formation, it is readily oxidized past this stage to yield the cor-, 
responding ketone and aldehyde groups, the final result being a 
break between the two carbon atoms initially united through the 
double union. The reaction has proven of great value as a means 
of structure proof. Write the equations for the subsequent 
steps in the oxidation of the above glycol. 

Acetylene and its derivatives of the type R-C=C-H form organo- 
metallic derivatives with ammoniacal cuprous chloride or with ammoniacal 
silver nitrate. R-C=C-Ag and R-C=C-Cu. These precipitates although 
explosive when dry, have been used for quantitative determinations. (Ber. 20, 
3081 (1887).) An alcohohc silver nitrate solution precipitates a double salt. 

R-C=CH+2AgN03 -* R-C^C-Ag-AgNOs+HNOs. 

Titration of the nitric acid liberated furnishes a volumetric method of 
analysis. 1 

It has already been pointed out that ethylene derivatives may under 
certain conditions add sulfuric acid to yield alkyl sulfuric acids from which 
the corresponding alcohol may be recovered. The analogous reaction may 
be applied to triple-bonded compounds, but the final product will be not an 
alcohol but an aldehyde or ketone. Write equations to illustrate such a 
reaction. 

The Saturated Aliphatic Hydrocarbons. — For the differentia- 
tion between the saturated aliphatic and aromatic hydrocarbons, 
the reactions typical of the benzene nucleus are apphed. The 
paraffin hydrocarbons are inert towards many of the reagents to 
which the members of the aromatic series respond; the most 
important reaction of the paraffins is substitution by halogens 
and this reaction is not suitable for qualitative application. The 
paraffin hydrocarbons usually met are the various fractions from 
petroleum and in dealing with these products special provision 
must be made for reaction due to the presence of not inconsider- 
able quantities of unsaturated products. 

1 Ann. chim. phys. (6) 15, 429 (1888); Ber. 25, 2249 (1892). 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 35 

The cyclo-paraffins, with the exception of cyclopropane, which behaves 
as an unsaturated hydrocarbon toward bromine (but not towards KMn04), 
are similar in reactions to the normal paraffins. This class of compounds is 
becoming of increasing importance because of the development of the cata- 
lytic nickel method for the hydrogenation of aromatic hydrocarbons. 

Problem 9. — Write the structural equation to illustrate the reaction 
between cyclopropane and Br2. 

Among the paraffin hydrocarbons, the greatest reactivity is 
found among members which possess a tertiary carbon atom, 
viz.: 



R 



R'^C-H 



The hydrogen on the tertiary carbon may be appreciably attacked 
by nitric acid, fuming sulfuric acid and by oxidizing agents. Sub- 
stitution by halogens also takes place more readily. It is neces- 
sary for this reason that the bromine titration of unsaturated com- 
pounds be carried out at a low temperature and in the presence 
of a diluent like carbon tetrachloride. For example, amylene, 
which possesses a tertiary carbon, adds bromine almost quantita- 
tively under the specified conditions. At a higher temperature, 
the tertiary hydrogen may become involved in the reaction. 

CHav cold CHsx 

>CH-CH=CH2 + Bra > >CH-CHBr-CH2 Br 

CH3/ ecu CH3/ 

Isoamylene 1, 2-dibromo-3-methyl butane 



soam 

Br2 CHss 



heat CHs" 



>CBr-CHBr-CH2Br + HBr 



1, 2, 3-tribronio-3-methyl butane 

Reactions of Aromatic Hydrocarbons. — The typical reactions 
of aromatic hydrocarbons are: 

1. Direct sulfonation, 

2. Direct nitration, 

3. Oxidation of side chains, 

4. Controllable halogenation, 

5. Reactivity in the Friedel and Crafts Reaction. 

These reactions are typical also of many derivatives of aro- 
matic hydrocarbons; in fact, the presence of certain substituents, 
like the amine and phenolic groups, may facilitate substitution 
into the benzene nucleus; on the other hand, certain other sub- 
stituents, like the nitro and sulfonic acid groups, will cause sub- 



36 



QUALITATIVE ORGANIC ANALYSIS 



stitution to take place with more difficulty. Nevertheless, among 
substitution products of aromatic hydrocarbons, these reactions 
are relatively unimportant from the standpoint of classification, 
but they are especially valuable for the preparation of derivatives. 

Application of direct sulfonation is the most convenient 
reaction for the differentiation of aromatic hydrocarbons from the 
saturated aliphatic type. The various aromatic hydrocarbons 
differ considerably in the ease of reaction with sulfuric acid; 
some members sulfonate slowly with concentrated (95 per cent) 
sulfuric acid without heating, others require concentrated acid 
with heating, while still others require fuming sulfuric acid occa- 
sionally with heating. The most convenient reagent for the dif- 
ferentiation is fuming sulfuric acid containing 20 per cent of the 
anhydride. The sign of reaction is the generation of heat and the 
gradual but complete solution of the hydrocarbon without exces- 
sive charring. Impure paraffin hydrocarbons may show consid- 
erable charring due to the presence of unsaturated compounds, 
but the main portion of the product is not attacked. 

Benzene reacts extremely slowly even with hot concentrated 
H2SO4. In fuming sulfuric acid (H2S04-S03), it dissolves readily 
and completely, considerable heat being liberated. The second 
sulfonic acid group enters less readily and the third group only 
with great difficulty. 

C6H5-S=0 + H2O 
\0H 

Benzene sulfonic acid /DO3XI 



SO3H 



SO, 



CeHg + H2SO4 



CeHs-CHs + HO-SO2-OH 




SO3H 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 37 



Toluene sulfonates more readily than benzene, while o- and 
w-xylene and mesitylene may be slowly sulfonated with 95 per 
cent H2SO4, even without heating. Para derivatives, such as 
p-xylene, dissolve less readily (separation of the xylenes), while 
p-dihalogen benzenes require 20 per cent fuming sulfuric acid and 
heating to 100° to 120° for sulfonation. Substitution in naph- 
thalene takes place more readily than in benzene and therefore 
concentrated H2SO4 may be used. 

.SO3H 



+H2SO4 




Mainly naphthalene-ot- 
~T" -tL2Vj sulfonic acid 



SO3H 



Mainly (85 %) naph- 
thalene-/3-8ulfonic acid 



Problem 10. — In the sulfonation of benzene with H2S04-S03, a trace of 
diphenyl sulfone is formed. Write the equation for the reaction. Separate 
a mixture of o- and p-chlorotoluene by means of sulfonation reactions. 

Although sulfonation is an important "classification reaction," it is of 
less importance as a "characterizing reaction." To be sure, the sulfonic 
acids may be isolated as the sodium salts, the latter converted (after drying) 
into the acyl chlorides and characterized either as such or in the form of 
the amides. More direct characterization methods are usually available. 
A few sulfonic acids may be isolated as such, but in general they are difficult 
to isolate because of their extreme solubility in water. 

Direct nitration, either with fuming HNO3 or with a nitrating mixture 
containing equal volumes of concentrated HNO3 (1.4 sp. gr.) and con- 
centrated H2SO4, is sometimes used for the differentiation between saturated 
aliphatic and aromatic hydrocarbons. Its disadvantage consists in the fact 
that the resultant nitration product often possesses a solubility behavior 
similar to that of the original unknown. Nitration is of greater value as a 
reaction for the preparation of derivatives. 

Oxidation of side-chains, with the resultant formation of carboxyl groups, 
is another typical reaction of aromatic hydrocarbons and of many of their 
derivatives. This reaction is of minor importance for the purposes of classi- 
fication but again it is of great value in the preparation of derivatives. It 
will therefore be discussed in Chapter X. 

Problem 11. — Review the rules governing the positions taken by sub- 
stituting groups introduced into the benzene nucleus. Place the groups 
NO2, OH, CI, Br, NH:, NH-COCHa, SO.,H, CH3, OC2H5 and CO2H approx- 
imately in the order of their directing abihty. Cf. Annual Reports 15, 75 
(1918). 



38 QUALITATIVE ORGANIC ANALYSIS 

Problem 12. — What organic acid is formed when 



CeH/ 



CH2-CH3 (1) 

CH2-CH2-CH3 (2; 



is oxidized with neutral or alkaline permanganate? 

Differentiation between Aromatic and Paraffin Hydrocarbons. 

— Differentiation between these two classes of hydrocarbons by 
means of the sulfonation test has already been discussed above. 
To some extent, sulfonation may be applied also when we are 
dealing with halogen derivatives of hydrocarbons, although usually 
considerable decomposition takes place with the evolution of 
halogen acid in the case of the chlorides and bromides and of free 
iodine in the case of iodides. Halogen attached directly to the 
benzene nucleus is stable toward sulfonation. 

A more convenient method for differentiation between the aro- 
matic and paraffin hydrocarbons is the dimethyl sulfate solubility 
test (page 135). The paraffin hydrocarbons do not dissolve 
appreciably in this reagent, whereas aromatic hydrocarbons in 
general dissolve in all proportions, due probably to the formation 
of an addition product between the ester and the aromatic nucleus. 
The aromatic hydrocarbons may be recovered from dimethyl 
sulfate by saponifying the latter with dilute alkali. This method 
of differentiation does not extend to the halogen derivatives of these 
hydrocarbons. 

The use of dimethyl sulfate^ is illustrated in the laboratory 
work. Special precautions must be taken in the use of this reagent 
since it is reported to be extremely toxic. 

The Reactivities of Organic Halogen Compounds. — Halogen 
compounds of a given type but differing in the nature of the halo- 
gen, possess the following order of reactivity toward the usual 
organic laboratory reagents: I>Br>Cl. Among the halogen 
substitution products of paraffin hydrocarbons, the reactivity 
for a given halogen united to tertiary, secondary, or primary 
carbon atoms respectively, is in the order mentioned, the tertiary 
halogen compound possessing the greatest mobility. Halogen 
compounds in which the halogen (X) is united directly to an 
unsaturated carbon atom of the type C = C, possess increased 

1 Chem. Ind. 23, 559 (1900). 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 39 

stability. Unsaturation on the /S-carbon gives increased activity. 
Substitution by oxygen on the a-carbon increases the activity. 

CH3-CH=CHX is more stable than CH3-CH2CH2X or 

CH2=CH— CH2X. 



/CH3 



• '^ ^^ 



C6H4\' is more stable than C6H5CH2X. ^.^.--^^y Qp flj^ 



} are very reactive. m n-n iian SS^^^ 

R-O-CH2X J 



Carboxylic acids that are aliphatic in nature and which possess 
a halogen on the gamma carbon exhibit greater reactivity toward 
elimination of HX (lactone formation) than do the a and /3 sub- 
stituted acids. 

H ^O Na2C03Sorn H 

CH3-C -CH2CH2C^OH > CH3-C-CH2-CH2-C=0 

Br i_0 ^ 



Lactone or inner ester 

The usual tests employed for determining the relative reac- 
tivities of halogen compounds are: 

(a) Reactivity towards tertiary amines, 
(6) Reactivity towards alcoholic KOH, 
(c) Reactivity towards alcoholic AgNOs. 

The reactions of organic halogen compounds with tertiary 
amines, resulting in the formation of quaternary ammonium 
compounds, has been used extensively for quantitative measure- 
^lents of reactivity the degree of which is usually expressed in the 
form of a velocity constant. Since the ammonium derivative 
formed in the reaction possesses ionizable halogen, the amount of 
reaction up to any given time may be determined conveniently 
by volumetric methods. 

Methods (6) and (c) are used more often in connection with 
qualitative work in the laboratory. A small amount (about 0.2 g.) 



40 QUALITATIVE ORGANIC ANALYSIS 

of the organic compound is dissolved in a few cc. of a 5 per cent 
solution of KOH in aldehyde-free ethyl alcohol. The mixture 
is boiled gently for about a minute and is then diluted with several 
volumes of water and acidified with HNO3. Any organic com- 
pound separating upon dilution must be removed by filtration, 
lonizable halogen in the aqueous solution is then tested for by 
means of the usual aqueous AgNOs reagent. 

The alcoholic AgNOs test is assigned in Chapter IX in con- 
nection with the laboratory work. It may be applied more rapidly 
than the alcoholic potash test and is almost as satisfactory. 
A saturated solution of AgNOs in absolute alcohol is used as a 
reagent, the alcohol serving as a common solvent for both the 
AgNOs and the organic compound to be tested. The test is not 
applicable to unsaturated compounds, some of w^hich may form 
insoluble addition products with AgNOs in alcoholic solution; 
neither should it be applied to compounds of the salt type. Cer- 
tain acidic substances may produce a precipitate of an insoluble 
silver salt which might be mistaken for silver halide. Care must 
be taken therefore in applying the test to substances of this char- 
acter. Water-soluble substances containing halogen should be 
tested with aqueous AgNOs after acidification with HNO3. 
But here also precautions are necessary similar to those taken 
with the alcoholic solution. 

The organic halogen compounds may be placed in four groups from the 
standpoint of their reactivity towards AgNOv 

(1) Water-soluble compounds containing ionizable halogen, or com- 
pounds such as acid halides of low molecular weight, which react 
readily with water to form ionizable halogen compounds, will 
react instantaneously, even with aqueous AgNOs. 

(2) Water-insoluble acyl halides, tertiary halogen compounds, etc., 
react instantaneously with alcoholic AgNOs. 

(3) Primary and secondary halogen compounds in the aliphatic series 
or aromatic compounds containing halogen in the side-chain, 
react slowly with alcoholic AgNOs but fairly rapidly on heating. 
Some chlorine derivatives are exceptions to this rule. 

(4) Aromatic halogen compounds containing halogen in the ring 
do not react even upon heating. Compounds of this type sub- 
stituted by a nitro group in the ortho position, however, possess 
considerable activity. 

The Friedel and Crafts Reaction is a method of introducing a side-chain 
into the benzene nucleus by treating an aromatic hydrocarbon with a reactive 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 41 

halogen compound in the presence of anhydrous aluminum chloride. The 
reaction is sometimes applied in order to differentiate between certain classes 
of halogen compounds. It is occasionally also used to differentiate between 
paraffin and aromatic hydrocarbons. The main objection to the test is that 
an appreciable quantity of pure material is required. 

Problem 13. — Explain exactly how the Friedel and Crafts Reaction may 
be applied in the laboratory in order to (a) differentiate cyclohexane from 
benzene, and (b) benzyl chloride from o-chlorotoluene. 

The Acyl Chlorides. — These compounds are chiefly of value as 
reagents for the testing of amines, alcohols, and phenols. When 
an unknown containing a very reactive halogen atom is suspected 
of being an acyl halide, the usual experimental conditions are 
reversed and a known amine is used as a reagent for the unknown. 

Problem 14. — Write the reaction which takes place between p-toluene 
sulfonj'l chloride and aqueous NH3. What is formed when the reaction 
product is treated with a slightly alkaline solution containing one mole of 
NaOCl? 

The Indifferent Oxygen Derivatives of Hydrocarbons: Alde- 
hydes, Ketones, Esters, Anhydrides, Alcohols, and Ethers. — 
With the exception of a relatively small number of members of 
low molecular weight (Group I), these compounds fall into Solu- 
bility Group V. Contrary to the usual assumption, relatively 
few members from the above series are decomposed by cold con- 
centrated sulfuric acid. Solubility in sulfuric acid without 
decomposition is by no means peculiar to the ethers. Differentia- 
tion between Groups V and VI, however, is not limited to solubility 
without decomposition; in fact, we have already discussed the 
behavior of the unsaturated hydrocarbons in this respect. Solu- 
bility with discoloration and partial polymerization will be noted 
especially with aliphatic aldehydes; ethers of the acetal type will 
readily hydrolyze; and marked decomposition will be noted with 
benzyl alcohol and its derivatives, a decomposition which may 
possibly be typical of many aromatic compounds with the 
— CH2OH side-chain. The complete decomposition of a product 
of the latter type with the production of solid products insoluble 
in concentrated H2SO4 must be accepted as evidence that the 
unknown is not a hydrocarbon. 

In testing for the compounds in Group V, the following order 
is preferable: 



42 



QUALITATIVE ORGANIC ANALYSIS 



TABLE XVI 

Solubility Group V, Aldehydks, Ketones, Esters (Anhydrides), 
Alcohols, Ethers, etc. Apply the Phenylhydrazine Test 



Positive reaction. 
Aldehyde or ke- 
tone. Apply tests 
to differentiate 

(Anhydrides will inter- 
fere. See page 45.) 



Negative test. 
Esters (anhydrides), alcohols, ethers, unsaturated HC. 
Apply saponification test 



Positive reaction. Es- 
ters and anhydrides 



Negative reaction. Alcohols, 
ethers, unsaturated HC. Ap- 
ply acyl halide test 



Po.sitive reac- 
tion. Alcohols 



Negative reac- 
tion. Ethers 
and unsatu- 
rated HC 



Both aldehydes and ketones possess the carbonyl group -C — 
and their most important reactions are therefore the typical 
reactions of this group. The speed of reaction of the carbonyl 
group, and, to some extent also the kind of reaction, is dependent 

upon the groups united to the carbonyl. In aldehydes, R-C — H, 
the carbonyl group is united to a hj'drogen atom, whereas in 

ketones R-C — R', the aldehyde hydrogen is replaced by a radical 
of higher molecular weight. In additive reactions, the aldehydes 
will therefore show a greater reaction velocity; individual ketones 
will exhibit decreased reaction velocity with increase in molecular 
weight of the radical R^ Differentiation between aldehydes and 
ketones may be based upon this difference in the ease of reaction. 

//^ . 
Since the hydrogen of the -C — H is readily oxidized to hydroxjd, 

another differentiation between aldehydes and ketones is found 

in differences in the ease of oxidation. 



The carbonyl group increases the mobility of the hydrogens on adjacent 
carbon atoms. For this reason, substitution by halogens takes place more 
readily with these classes of compounds than with the hydrocarbons. 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 43 

O 

II /OH Br2 
R-C-CH2-R :;± R-C=CH-R > 

Enolic form 
of ketone 

/OH 



R-C— CHBr-R 
I 
Br 



R-C— CHBr-R+HX 



A methylene (CH2) group adjacent to the carbonyl group is often spoken 
of as a reactive methylene. It takes part more readily in condensation, 
oxidation, halogenation and other reactions than does the normal methylene 
group in hydrocarbons. 

A methylene group adjacent to two carbonyl groups exhibits unusual 
reactivity, due to an increase in the amount of enolization. Such com- 
pounds form sodium salts with alcoholic sodium ethylate and are of con- 
siderable importance in synthetical work. Some of these enols may behave 
toward alkali treatment in a manner suggestive of the saponification of esters. 

O O 

II II /OH ^O NaOHsol'n 
CH3-C-CH2-C-CH3 ;=i CH3-C=CH-C— CHs > 

Acetyl acetone -l-heat 



o 

II 

CH3-C— ONa +CH3-C-CH3 



./^ 



Although the various reactions just discussed are seldom used for classi- 
fication purposes in elementary analytical work, they are of importance in 
connection with possible interference with the usual tests. 

Problem 15. — Write the reactions for (a) the ketone spUtting of aceto- 
acetic ester, and (6) the acid splitting of the same ester. 

Problem 16. — Upon saponifying an ester with concentrated alkali, an 
alcohol and an acid are obtained. Which classes of aldehydes also yield 
acids and alcohols under similar treatment? Write the equations. 

Other common classes of compounds which, according to the 
Hnking theory, possess carbonyl groups, are carboxylic acids, 
esters, amides, acyl halides, etc. These groups, however, do not 
exhibit the typical carbonyl condensation reactions. 

General Test for Aldehydes and Ketones. — Phenylhydrazine 
reacts with both aldehydes and ketones to yield phenylhydra- 
zones. The reaction is catalyzed by the presence of a weak acid 
like acetic, but strong acids may prevent the reaction; for 
example, phenylhydrazine hydrochloride may not react unless 
an equivalent amount of sodium acetate is added. The sign of 



44 QUALITATIVE ORGANIC ANALYSIS 

reaction is the formation of a sparingly soluble phenylhydrazone, 
which is insufficiently basic to dissolve in dilute acid. 

When a clear solution of phenylhydrazine in dilute acetic acid 
is added to a dilute aqueous solution of an aldehyde or ketone of 
low molecular weight, an immediate and almost quantitative 
precipitation of the corresponding phenylhydrazone is noted. 
For water insoluble carbonyL compounds, a modified procedure is 
proposed (Chapter IX). When the phenylhydrazone of an 
unknown is found to be a solid, it may be recrystallized and used 
as a derivative. 

H 

R\ H\ I y V dilute acetic acid 



C=0 + ^N-N— < > > 



H(RO 

H H 

R\ /OH I I . 



H(RO 



H 

R\ I 

\C=N-N 

H(R') 



> 



Intermediate product Phenylhydrazone of the 

aldehyde or ketone 

This reaction has been adapted to quantitative volumetric 
work^ as is also the case with certain other condensation reactions, 
particularly the reaction with hydroxylamine.^ 

In addition to the condensation with phenylhydrazine, the 
aldehydes and ketones undergo analogous reactions with other 
substituted ammonias. This topic will be discussed further in 
connection with the preparation of derivatives, in Chapter X. 

Discussion of the Phenylhydrazine Reaction. — The dilute acetic acid 
solution of phenyldrazine should be prepared just before using. After it 
has been allowed to stand even at room temperature for several days, an 
appreciable amount of the sparingly soluble acetyl derivatives of phenyl- 
hydrazine will have formed. In general, the phenylhydrazones are much 
less soluble in various solvents than are the corresponding aldehydes and 
ketones. A convenient method of applying the test to water insoluble 
compounds therefore consists in dissolving the carbonyl compound in a small 
amount of alcohol and adding water drop by drop until the solution is exactly 
at the saturation point. An amount of pure liquid phenylhydrazine equal 
to that of the unknown is then added. In the case of most aldehydes, an 

1 Monatsh. 13, 299 (1892). ' - « Analyst 34, 14 (1909). 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 45 

almost immediate precipitation of the phenylhydrazone takes place, due 
to the fact that it is less soluble in the dilute alcohol than is the aldehyde. 
If no precipitation takes place within one minute's time, one drop of glacial 
acetic acid is added in order to catalyze the reaction. 

The various ketones differ greatly in their speeds of reaction with phenyl- 
hydrazine, some precipitating after a few seconds, others after several 
minutes, whereas members of very high molecular weight may require a 
considerably longer time. The rapid reaction of most aldehydes without the 
addition of a drop of acetic acid to act as a catalytic agent may possibly be 
explained by the fact that many of the aldehydes contain a trace of acid as 
an impurity. Aldehydes of special purity show slower reactions, corre- 
sponding more closely to the ketone reaction. 

A number of salts of phenylhydrazine are only sparingly soluble in water; 
this is true of the oxalate, sulfate, phosphate, etc. It is therefore important 
that this be kept in mind when phenylhydrazine is used in testing for the 
presence of aldehydes or ketones in aqueous solutions which might contain 
also other substances. 

Among the esters, a few members, for example, methyl oxalate, may be 
sufficiently reactive to combine with the reagent to form an acyl derivative, 
the precipitation of which might be confused with the test for the carbonyl 
group. This is true also of the anhydrides. 

Phenylhydrazine is important in testing certain sugars (Chapter V). 

In addition to the phenylhydrazine test, many other reactions may be 
adapted, with suitable limitations, as tests for the carbonyl group. In 
general, these reactions are not as convenient and satisfactory as the test out- 
lined above. The formation of addition products with sodium acid sulfite is not 
as general as is often suggested in text-books. Aldehydes and low molecular 
weight ketones react readily but the higher ketones and particularly aromatic 
ketones show very little reaction, particularly when the ketone group is 
adjacent to the aromatic nucleus. The reaction is almost as satisfactory for 
differentiation between aldehydes and ketones as for a general test, and 
somewhat unsatisfactory for either purpose. The sulfite addition products 
are sometimes quite soluble in water. ^ 

.0 /OH 

R-Cf + NaHSOs -^ R-C^O-SO.Na 
^H \H 

The reaction is often of value in purifying aldehydes and ketones. The 
organic compound may be recovered by treatment with either dilute acid or 
alkali (Na2C03). A common source of error in applying the test to an 
alcoholic solution of an unknown consists in a precipitation of the sodium 
bisulfite itself, due to its lower solubihty in alcohol. 

Problem 17. — Write structural equations for the following reactions: 
(a) Benzaldehyde and concentrated alkali in the Cannizzaro reaction, 
(6) formaldehyde + ethyl alcohol in the presence of a small quantity of dry 
HCl, (c) a ketone -1- aqueous HCN, {d) acetone H-an aqueous solution of 



46 QUALITATIVE ORGANIC ANALYSIS 

NH4CI and KCN, (e) acetaldehyde+NHs in dry ether, (/) benzaldehyde or 
furfural + aqueous NH3, (g) benzaldehyde + aniline (alcoholic solution), (h) 
magnesium ethyl bromide and n-heptanal. 

The Differentiation between Aldehydes and Ketones. — 

(a) The Ammoniacal Silver Nitrate Test. Aldehydes are readily 
oxidized with ammoniacal silver nitrate solution, whereas ketones 
are more stable. 

O /in sol'n as \ ^Q 

R-Cr + AgsOl Ag(NH3).0Hl -^ R-C^0-NH4+ 2Ag j 

(b) The Fuchsin Aldehyde Test. — Aldehydes restore color to 
Fuchsin Aldehyde Reagent whereas ketones do not. The reagent 
is a dilute solution of rosaniline or fuchsin hydrochloride (magenta) 
that has been decolorized by sulfur dioxide. 

Rosaniline HCI+2H2SO3 

Crimson color. _^ (H2N • C6H4)2 : C • C6H4 • NH • SO2H 

I 
S03H 

Colorless- 

The aldehyde reverses this reaction due to a removal of H2SO3 
from the methane carbon and a regeneration of the quinoid hnk- 
age. The restored color is not identical with the original fuchsin 
color but possesses a distinct bluish tinge. This is due to a reac- 
tion between the aldehyde and amino groups. The recently pro- 
posed formula for the aldehyde-dye, 

(R-CHOHOSONH-CgH4)2 : C : C6H4 : NH 

(Ber. 54, 2534) is still open to question. 

In general those reagents which remove sulfurous acid will 
restore the fuchsin color. This is true of organic amines, inorganic 
alkahs, and even of certain hydrolysable salts. Heating the 
reagent restores the color due to the dissociation of the fuchsin- 
sulfite compound. Although the restored color lacks the typical 
bluish tinge produced by aldehydes, it is always advisable to 
apply the test in the cold and to bear in mind the possible inter- 
ferences. 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 47 

General Test for Esters and Anhydrides. — When a compound 
responds to a test for an aldehyde or ketone, other reactive groups 
may of course be present also. If such should be the case, evi- 
dence will be found in connection with the subsequent tests, and 
particularly in connection with the physical constants of the 
unknown and its derivatives. Consultation of tables of physical 
constants before applying class reactions is unjustifiable and liable 
to cause unnecessary work because it is apt to be misleading. 
On the other hand, after a typical group has been located, then 
physical constants will be of value in indicating other possible 
groups to be tested for (with due consideration for complications 
caused by the simultaneous presence of several groups). 

The general test for esters (including lactones) and anhydrides 
is saponification with alkali. Ethers will remain unaffected under 
the experimental conditions chosen, but aldehydes may be 
decomposed. See Problem 17. 

Problem 18. — Write structural equations to illustrate the saponification 
of (a) phenyl salicylate, (6) benzoic anhydride, and (c) nitroglycerol. 

Differentiation between Esters and Anhydrides. — Three com- 
mon classes of compounds contain an oxygen atom uniting two 
carbon atoms, viz.: 

R-CH2-O-CH2-R Ether, 



R-C^O-CHsR Ester, and 

O O 

II II 

R-C— 0-C-R Anhydride. 

The ethers are stable towards the usual alkali treatment. In 

the esters, the -C— structure has greatly weakened the -C-O-C 

linkage. It is logical therefore to expect that a compound pos- 

O O 

II II 

sessing two carbonyl groups joined through oxygen, -C — 0-C-, 
will be unusually susceptible to hydrolysis. This is true, and we 



48 QUALITATIVE ORGANIC ANALYSIS 

may therefore differentiate the anhydrides from the esters by 
(a) the great susceptibility of the former type to undergo hydrol- 
ysis and (6) the fact that the hydrolysis of the former produces 
no alcohol as a by-product. Very often the hydrolysis of anhy- 
drides may be carried out in the cold with dilute alkali. Esters 
usually require refiuxing with strong alkah, sometimes in alco- 
holic solution. 

It should be remembered, however, that some esters of polycarboxylic 
acids, such as oxalates and malonates are hydrolyzed very readily. Methyl 
and ethyl formate, methyl acetate, etc., are also rapidly hydrolyzed in 
aqueous solution but the boiling-points (below 130°) of the latter compounds 
exclude the possibility of anhydrides. Explain. 

The acyl haUdes may be considered as mixed anhydrides; they are, 
however, differentiated from the usual anhydride in connection with the 
elementary analysis. 

A logical method for differentiating an anhydride from an ester is based 
upon the fact that the anhydride can react with an alcohol to produce one 
mole of ester and one mole of free acid. An anhydride of a dicarboxylic acid 
will react to produce an acid ester. 

O Q 

c/ /\ /C^O-R 




O + ROH 
C^^ \/ \C^OH 

o 

Additional reactions of anhydrides are discussed in the following chapter 
in connection with the tests for amines. The use of such reactions is 
reversible, and amines may be used as reagents to test for anhydrides. 

Differentiation between Alcohols and Ethers. — Alcohols may 
be differentiated from ethers by the usual reactions of the hydroxy! 
group, viz.: 

(1) Reaction with metallic sodium, 

(2) Reaction with acyl haUdes and anhydrides, 

(a) Acetyl chloride, 
(6) Benzoyl chloride, 

(c) Other acyl halides, 

(d) Anhydrides, 

(3) Reaction with phenyl isocyanate. 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 49 

The most common interfering substance is water. The enoHc 
forms of aldehydes, ketones, and tautomeric esters also possess 
-OH groups and will respond to some of these tests, particularly 
to the metallic sodium test. It is partly for this reason that tests 
for aldehydes, ketones, esters, etc., precede tests for alcohols. 

^O /OH /ONa 

/C^OR ^C^O-R Na ^C^OR 

CH2< //O ^ HCf /O > H-Cf /O + H 

\C^OR \C^O-R \C^OR 

O 

II /OH Na /ONa 

CH3-C-CH3 ^ CH3-C^CH2 > CHs-C^CHa + H 

/O 2Na 

'y ( 



2CH3-C^OR 



trace of alcohol as impurity 



/ONa /O 
CH3-C=C— C^OR + R-ONa + H2 
H 



The Use of Acyl Halides or Anhydrides is more satisfactory 
than that of metallic sodium since the enolic forms of most alde- 
hydes and ketones are not detected by these reagents. 

R'-O-H + R-C^Cl -> R-C^O-R' + HCl 

^0 
R-O-R + R-C^Cl -^ No reaction if pure. 

H-O-H + R-C^Cl -^ R-C^OH + HCl 

One cc. of the unknown is treated cautiously with 1 cc. of 
acetyl chloride. The signs of reaction are the evolution of heat, 
the liberation of hydrochloric acid gas, and the formation of an 
ester. The fact that esterification has taken place is indicated by 
the odor of the reaction product after it has been poured into a 
small amount of water to remove the excess of acetyl chloride; 
a mere trace of alcohol as impurity in an ether might also be respon- 



50 



QUALITATIVE ORGANIC ANALYSIS 



sible, however, for an ester odor. Change in solubihty is another 
sign of reaction, as is indicated in Table XVII below. 

TABLE XVII 



Alcohol 


Solubility of the 

alcohol. Grams per 

100 grams of H2O 


Solubility of the 

acetyl derivative. 

Grams per 100 grams 

of H2O 


Ethyl 


GO 
00 

10 
9 
2.5 


8.0 


Propyl 


1.5 


Isobutyl 


0.7 


n-Butyl 

Isoamyl 


0.6 
0.2 



A change in other physical properties, such as conversion of a 
liquid unknown to a solid derivative, is another indication of 
reaction. In special instances, the reaction product may be 
isolated, washed free from acids, and the presence of the acetyl 
group determined by saponification tests (page 140). 

In the acylation reaction, primary and secondary alcohols behave in the 
normal manner but tertiary alcohols often react to produce halogen deriva- 
tives of hydrocarbons. 



R'-^C-OH + CHa-C^Cl 
R' 



R 



7' 



y/\ 



o 



R'-^C-Cl + CHa-C^OH 
R"/ 



Benzoyl chloride possesses the advantage over acetyl chloride in that it is 
only very slowly decomposed in cold water and therefore it may be used 
in detecting alcohols even in aqueous solution, since the -OH group in the 
alcohol reacts much more rapidly with the acyl chloride than does the -OH 
group of water. The reaction is usually carried out in aqueous solution 
containing sufficient alkali to decompose any e.xcess of benzoyl chloride into 
the water-soluble benzoate. The benzoyl esters formed are insoluble in 
water. 

The substance most frequently interfering with the acetyl chloride test 
is water. The -OH groups of most phenols act similarly to the alcoholic 
-OH group. Ammonia, primary amines, and secondary amines react 
unusually readily with the acyl halides and anhydrides and therefore special 
precautions must be used in applying the test to nitrogenous compounds. 

Phenylisocyanaie Test. — Alcohols and phenols react with isocyanates in 
the manner indicated by the subsequent equations, the latter the more 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 51 



readily. One of the common reagents used in organic laboratory work is 
phenylisocyanate. 

O 




— N=C=0 + H-0- 



N=C=0 + H2O 



H 

— NH + CO2 



H II , . 

C6H5-N=C=0 




\/ 



The presence of moisture interferes with the reaction and the reagent is 
also sensitive to ammonia and to the amines. With a few exceptions, the 
usual acyl anhydrides do not react with the enols, whereas phenylisocyanate 
has found considerable application as a reagent to detect the enolic forms of 
certain tautomeric compounds. 

The Differentiation between Primary, Secondary and Tertiary Alcohols. — 
Primary, secondary and tertiary alcohols differ greatly in their reaction 
velocities in esterification with acetic acid; these velocities^ are approximately 
as follows: I : II : III : : 40 : 20 : 2. The amount of esterification which has 
taken place in a given time under standardized conditions therefore is of 
considerable value in differentiating between the various classes of alcohols. 
For general qualitative work, it is scarcely adaptable, since several hours 
are required for the determination. 

The Hydrobromic Acid Method. — Most tertiary alcohols react very 
quickly with 48 per cent hydrobromic acid to give a good yield of alkyl 
bromide. Secondary alcohols react fairly rapidly when they are refluxed 
with the hydrobromic acid solution, whereas primary alcohols react slowly 
upon refluxing but quite rapidly when one mole of H2SO4 is used for every 
two moles of hydrobromic acid.- 

The Phthalic Anhydride Test. — Phthalic anhydride reacts with primary 
alcohols when a benzene solution of the two compounds is refluxed. Secondary 
alcohols react less readily and it is usually necessary to heat the mixture 
of anhydride and alcohol to a temperature of from 100° to 120°. Tertiary 
alcohols do not react. 

The Victor Meyer Method is adaptable mainly to alcohols of low molecular 
weight. These alcohols are converted into the corresponding nitro com- 
pounds through the iodides. Primary, secondary and tertiary nitro com- 
pounds may then be easily differentiated. The tertiary nitro compound 
does not dissolve in dilute alkali, while the other two members are alkali- 
soluble, due to their ability to exist in an aci-form. The last two may be 

1 Weyl, Methoden, Part II, p. 756 (1911). 

2 J. Am. Chem. Soc. 42, 299 (1920). 



52 QUALITATIVE ORGANIC ANALYSIS 

differentiated by their action towards nitrous acid. The secondary nitro 
compound forms a nitroso derivative which is no longer soluble in alkali 
and which usually possesses a characteristic color. The primary nitro 
compound forms a nitroso compound which is alkali-soluble because of its 
ability to exist in the isomeric oxime form. Although the Victor Meyer 
test is rather limited in its application to alcohols, the same reactions are 
of value for the differentiation between I, II, and III alkyl iodides and I, 
II and III aliphatic nitro compounds. For this reason it deserves mention 
here. 

Problem 19. — Write equations to illustrate the reactions involved in the 
Victor Meyer method for the differentiation between I, II and III alcohols. 
Weyl, p. 753 (1911). 

Neutral Compounds of Group I. — Aldehydes, ketones, and 
alcohols of low molecular weight, together with a few esters, are 
found in Solubility Group I, since they are soluble in water and 
also in ether. They will usually, but not always, be met as liquids. 
When a substance is located in Group I, the aqueous solution of 
the unknown is immediately tested for acidity, so as to differen- 
tiate the neutral from the acidic substances. If the aqueous 
solution is acid to litmus, a portion of the unknown, about 0.2 g., is 
titrated with 0.1 N. alkali, using phenolphthalein as an indicator. 
Small amounts of acid, often inorganic, may be present as impuri- 
ties and it is important therefore to know approximately the 
amount of acidity, 

A few esters in Group I will produce acid reactions and this is 
true of all the water-soluble anhydrides. Upon titration, the 
former will be neutralized gradually, whereas the water-soluble 
anhydrides are saponified more rapidly. 

Problem 20. — How many cc. of 0.1 N alkali are required to neutralize 
(a) 0.1 g. of propionic acid, (b) 0.1 g. succinic anhydride, (c) 0.1 g. aniline 
sulfate, and (d) 0.1 g. methyl oxalate assuming that only one ester group is 
rapidly saponified? Phenolphthalein is used as the indicator. 

. The discussion of reactions of neutral oxygen compounds and 
the order of applying tests in Group V applies directly to the 
corresponding compounds in Group I, variations being in degree 
only, since the low molecular weight compounds differ mainly in 
possessing greater rates of reaction towards the reagent employed. 
The low molecular weight aldehydes and ketones will react with 
phenylhydrazine almost instantaneously, whereas a ketone, like 
O 
II 
benzophenone, CgHs-C-CoHs, reacts comparatively slowly. 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 53 



Aldehydes of Group I react unusually rapidly with ammoni- 
acal silver nitrate and with fuchsin aldehyde reagent. Similarly, 
esters and anhydrides undergo hydrolysis more readily than the 
corresponding classes in Group V, a reaction which is aided partly, 
of course, by the fact that the compounds are water-soluble. 
Several esters in this group react so readily with water, ammonia, 
and the amines, that they might be mistaken for anhydrides by 
the uninitiated. However, they yield both acids and alcohols 
upon hydrolysis. 



C^OCHs 
C^OCHs 



+ 2NH3 



C^NH2 
C^NHa 



C^OCHa 



H 



/- 



+2 N-. 
O H \ 



C^OCHs 



C^— -N- 



C 



/ 



OH 

-N- 



The Ipdoform Test. — Compounds in Group I which possess 

the aceto group \CH3-C— / united to either carbon or hydro- 
gen, or compounds which are oxidized to this structure under the 
conditions of the experiment, will respond to the iodoform test. 
(Exp. 10, Chapter IX.) A positive test consists in the precipi- 
tation of iodoform when a dilute (5 per cent) solution of the 
unknown is treated with NaOI solution, either in the cold or upon 
warming to 60° during a few minutes time. The reactions involved 
are as follows: 

^O /OH NaOI 

C H3— C — CH3 



/OH 
CH3-C=CH2 - 

/OH 

CHg-C^CHoI 

I 
ONa 



O 
II 
CH3-C-CH2I + NaOH 



Enolization of the ketone and addition of NaOI again takes 
place and results in the formation of: 

CHs-C^Cei 
\I 



54 QUALITATIVE ORGANIC ANALYSIS 

a compound unstable in the presence of alkali. 

CH3-C^C^I + NaOH -^ CHs-C^ONa + CHI3 
\I 

Problem 21. — Classify the following compounds into two groups, (a) 
those which will respond to the iodoform test, and (6) those which will fail 
to yield iodoform under the usual experimental conditions: 
/ (1) acetone, — (5) acetic acid, (9) propionaldehyde, 

(2) methyl alcohol, (6) isobutyl alcohol, (10) levulinic acid, 

^ (3) ethyl alcohol, (7) secondary butyl al- (11) pyruvic acid, 

(4) propyl and isopropyl cohol — (12) acetoacetic ester, 

alcohols, • — (8) acetaldehyde, (13) diethyl ether. 

Acidic Compounds. — The main acidic compounds containing 
only the elements C, H, and O are the carboxylic acids and the 
phenols. These compounds are found mainly in Group IV, 
although the water-soluble members will be found divided between 
Groups I and II. A relatively small number of phenols belong 
to the alkali-insoluble class and are liable to be classified in Group 
V (see Chapter II, problem 3). 

The majority of phenols are feebly acidic in comparison with 
the carboxylic acids; the latter may be titrated quantitatively 
in aqueous solution using phenolphthalein as an indicator, but 
this is not true of the phenols. Methods of classification, such as 
the following, have been proposed, but are so obviously open to 
exceptions that a brief discussion is necessary. 

[ Soluble in alkah but precipi- 
tated upon saturating the 

(1) Phenols \ solution with carbon di- 
oxide. 

Insoluble in NaHCOs solution. 

(2) Weak Carboxylic Acids f Soluble in NaHCOs solution 

(not negatively substi- \ but insoluble in sodium for- 
tuted) i mate solution. 

(3) Strong Carboxylic Acids, 

particularly dicarbox- 
ylic acids, nitro car- 
boxylic acids, etc 

Sulfonic Acids, etc 

The above classification may lead to error because it does not 
take into consideration the water-solubility of the individual 



Soluble in sodium formate 
solution. 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 55 

compounds. The partition of a base between two acids is con- 
trolled not only by the respective strengths of the acids, but also 
by their concentrations. In substances very sparingly soluble in 
water, the concentration of the dissolved substance is greatly 
limited and this is the reason that certain acids, although strong 
acids, are precipitated by carbon dioxide; on the other hand, 
many phenols are sufficiently soluble in water to fail to precipi- 
tate with carbon dioxide. This method of differentiation must 
be used, therefore, with proper appreciation of its limitations. 

Certain other classes of acidic compounds, such as imides, 
sulfonamides, etc., when only sparingly soluble in water, can be 
precipitated from their sodium salts by means of carbon dioxide. 

Differentiation between Phenols and Acids. — Although the 
above solubility differentiation for these two classes of compounds 
possesses a certain value when applied in the light of the limita- 
tions, a more valuable method of differentiation is available 
because of the fact that the phenol group increases enormously 
the velocity of bromine substitution in the benzene ring. The 
sign of reaction in carbon tetrachloride is the evolution of copious 
amounts of hydrobromic acid. When the test is conducted with a 
dilute aqueous solution of a phenol, the sign of reaction is the 
formation of a sparingly soluble bromine substitution product. 

OH 

-Br+HBr 
^"^ /^ Br\ 0,H OH 



OH Br/Y ^™' 



^ 



Br 
COoH 



/ Br Br 



ecu sol'n. No reaction under experi- 
+Br2 > mental conditions. 

\y 

CH3-(CH2)4-C02H+Br2 > No reaction under experi- 

CCI4 sol'n mental conditions. 



56 QUALITATIVE ORGANIC ANALYSIS 

Discussion of the Reaction and of Its Limitations. — The reaction between 
phenol and bromine takes place very readily at room-temperature, the 
second and third atoms of bromine substituting almost as readily as does 
the first to produce tribromophenol. Most substituted phenols also show 
great reactivity, as is indicated below, but replacement of the H of the 
phenolic — OH group by alkyl or acyl radicals decreases the reactivity. 

Problem 22. — Write the reactions between bromine and (a) sahcylic acid, 
(b) p-nitrophenol, and (c) fluorescein. 

The phenohc structure adds to the ease of substitution into the benzene 
ring, not only of bromine, but of other groups, such as chlorine, nitro, sulfonic 
etc.; it also tends to the instability of the aromatic nucleus toward perman- 
ganate o.xidation. In order to oxidize side-chains in the presence of the phenol 
group, it is necessary to protect the latter. How? The amine group also 
increases the ease of substitution in the aromatic nucleus and this fact must 
be remembered in testing basic compounds. Bromine in carbon tetra- 
chloride may also attack certain aldehydes, ketones and esters, both in the 
aliphatic and the aromatic series. This is true especially among the types 
which exist to a considerable extent in the enolic forms, since the mechanism 
of substitution in such cases is no doubt first an addition of bromine to the 
enoUc form, followed by the elimination of hydrobromic acid. The use of 
carbon tetrachloride as a diluent possesses the advantage in that bromine is 
more readily handled, it acts as a solvent for the organic compounds, hydro- 
bromic acid is insoluble in this solution, and the reaction velocity is somewhat 
lowered. A number of hydrocarbons which react readily with liquid bromine 
react only slowly in carbon tetrachloride solution. 

Phenols having para or ortho positions unoccupied couple readily with 
diazonium compounds; tliis is simply another example illustrating the ease 
of substitution. 

The Ferric Chloride Phenol Test.^ — Many phenols give typical 
blue, green, purple, or red colors when a drop of ferric chloride is 
added to a dilute aqueous solution of the unknown. A number 
of phenols which do not give this test readily are found to respond 
when tested in alcoholic solution. Among the carboxy deriva- 
tives of phenol, those having the carboxyl group ortho to the 
phenolic hydroxyl, as in salicyhc acid, respond with a typical deep 
purple color, but many compounds with the carboxyl group in the 
meta or para position fail to respond to the test. 

.CO2H /CO2H 



\ /\ CI 

O-Fe/ + HCl 
\C1 



^OH -f FcCls ^ 

iCf. Ann. 323, 1, 10, 20 (1902). 



CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 57 

Typical enols, which, like the phenols, possess an -OH group united 
to the unsaturated carbon, give deep red colorations, a fact which has been 
used in connection with the investigation of tautomeric substances. 
a-Hydroxy acids may produce a yellow color and some common aliphatic 
acids, like acetic, give the well-known red color under suitable experimental 
conditions. Example: The quaUtative test for acetic acid in inorganic 
chemistry. 

.Other Reactions of the Phenol Group. — The phenolic group possesses many 
reactions in common with the alcohohc group; thus, acyl chlorides react 
readily with most phenols to form esters. Diphenyl carbamine chloride, 

/^ 
(C6H6)2N-C — CI, a common reagent used in preparing derivatives of the 

phenols, is more reactive toward the phenolic than toward the alcoholic 

group and this is true also of alkyl sulfates which react readily with the 

sodium salts of phenols to produce alkyl ethers. Several of the common 

phenols may be condensed with phthalic anhydride to produce phthaleins. 

Reactions of the Carhoxyl Group. — Important reactions of the carboxyl 

group, — C — O— H, are (a) salt formation, (6) esterification, (c) formation 
of acyl halides, (d) formation of amides, and (e) loss of CO2. 

Salt formation is typical of all the compounds listed in Group IV. A 
partial differentiation between the various members of this group has already 
been considered in connection with the differentiation of the carboxylic and 
sulfonic acids from the weakly-acidic substances upon the basis of solubility 
in NaHCOs solution. Acidic compounds should be titrated with standard 
alkali (p. 138) and the neutral equivalents determined. The carboxyHc acids 
will give practically the same neutral equivalents whether the titrations 
are carried out in aqueous or alcoholic solution. Feebly acidic compounds 
will show an abnormally high neutral equivalent, especially when titrated 
in aqueous solution. 

Important reactions, such as esterification, the formation of acyl halides 
and amides, anhydride formation of certain dicarboxylic acids, and related 
reactions will be illustrated in 'the section dealing with the preparation of 
derivatives. 

Problem 23.— Although the compound, H-0-^^^^ ^>— C— NH2, does 

not contain a carboxyl group, it yields an ethjd ester when refluxed with 
alcoholic HCl. By means of equations, write the reactions involved. 

Volatility Constants of Aliphatic Acids. — The mono carboxylic 
derivatives of the paraffin hydrocarbons up to and including those 
containing six carbon atoms are readily volatile with water vapor. 
These acids differ very widely in their degrees of volatility when 
diluted solutions are subjected to distillation, and accordingly 
Du Claux^ has based upon this fact a quantitative method for the 

1 Ann. chim. phys. [5] 2, 289 (1874); Analyst 20, 193, 217 (1895); J. Am. 
Chem. Soc. 39, 731, 746 (1917). 



58 QUALITATIVE ORGANIC ANALYSIS 

estimation of individual acids and for some of their mixtures. 
Although open to certain objections from the quantitative stand- 
point, the method is of considerable value in connection with 
qualitative organic analysis, and is therefore presented in 
Chapter IX, Exp. 16. 



CHAPTER IV 

CLASSIFICATION REACTIONS OF THE SIMPLE NITROGEN 
AND SULFUR COMPOUNDS 

BASIC NITROGEN COMPOUNDS 

With a few exceptions, the basic organic compounds contain 
nitrogen. When solubility tests have placed a compound in 
Group III but elementary analysis has failed to prove the pres- 
ence of nitrogen, it will be advisable to repeat the tests for the 
elements. The most important basic nitrogen compounds are 
the amines; the discussion in Chapter II has dealt with the effect 
of various substituting groups upon the basicity of the amine 
group and this section (pp. 19-21) should be reread in connec- 
tion with the present discussion. 

The first test to be apphed to basic compounds is the acylation 
test: Ammonia, primary amines, and secondary amines are 
readily acylated, whereas tertiary amines usually undergo no 
similar reaction although in the latter case addition products with 
acyl halides may be formed.^ 

The most important acylating agents used in the laboratory 
are: 

(1) Acetyl chloride and acetic anhydride, 

(2) Benzoyl chloride, 

(3) Benzenesulfonyl chloride, 

(4) Phthalic anhydride. 

As has already been pointed out in Chapter III, the acyl 
halides and anhydrides react readily with the hydroxyl groups of 
alcohols and phenols. This fact must be kept in mind in connec- 
tion with tests for amines. Acid chlorides of low molecular 

^ Dehn, J. Am. Chem. Soc. 36, 2091 (1914). At higher temperatures, an 
alkyl group may be replaced by the acyl group. Ber. 19, 1947 (1886). 

59 



60 QUALITATIVE ORGANIC ANALYSIS 

weight, particularly acetyl chloride, react readily with water. 
Benzoyl chloride, benzenesulfonyl chloride, and similar deriva- 
tives, however, may be safely used to test for amines in the pres- 
ence of water. Why? 

H 

2C6H5-NH2 + CHs-C^Cl -> CeHs-N-C^CHs + CeHg-N^H 

|\h 

CI 

o 

C6H5-NH2+CH3-C-0-C-CH3 -^ 

CeHs-N^ C^CHa + CHsC^OH 

In the above equations, it should be noted that acetyl chloride 
does not convert aniline completely into the acetyl derivative 
since the by-product, aniline hydrochloride, is formed and this 
does not act readily with the reagent. On the other hand, with 
acetic anhydride the amine is converted quantitatively into the 
acyl derivative and therefore this latter reagent is of more im- 
portance in connection with the preparation of derivatives. It 
is also of value in quantitative estimations of the amine group, the 
excess of acetic acid which remains after the reaction being deter- 
mined volumetrically. Benzoyl chloride, benzenesulfonyl chlo- 
ride, and other acyl halides that may be used in aqueous solution 
may also convert the amine completely into an acyl derivative 
for the reason that they are usually used in the presence of alkali 
which will combine with the hydrochloric acid generated in the 
reaction. When benzoyl chloride is used, a small amount of 
benzoic acid may be formed, due to the following side-reaction: 

C6H5-C^Cl+2NaOH -> CoHs-C^ONa-FNaCl+HaO 

The slight excess of benzoyl chloride that is generally used in the 
reaction must be destroyed completely in order to prevent it from 
contaminating the derivative. The benzoic acid, however, 
remains in the solution as sodium benzoate, whereas the benzoyl 
derivative of the amine is insoluble in alkali unless some acidic 
group like carboxyl is simultaneously present. 

Problem 24. — Criticise the following laboratory test: One-half cc. of the 
unknown (basic compound, b.p. 190°-195°) was treated with an equal 
volume of acetyl chloride. A violent reaction took place and a solid deriva- 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 61 



tive was formed. A portion of this solid was removed from the test tube 
and transferred to a clay-plate in order to remove most of the adhering oil 
and finally was washed by several applications of ether. The snow-white 
crystals remaining failed to check in melting-point with the acetyl deriva- 
tives of any amine boiling in the neighborhood of 190°-195°. 

The acyl halides and anhydrides react with the amine group 
more readily than with the hydroxyl group. For example, when 
an amino phenol is treated in water solution with one mole of 
acetic anhydride, the acetyl group will substitute the amine 
hydrogen atom far more rapidly than the hydrogen of the 
hydroxyl group. 



/ 



CHs 



O 



/- 







4- CHs-C^O-C-CH 



^OH 



•N^ 



-C^CHs 



+ CH3-CO2H 



\ 



OH 



In ortho aminophenols, acyl groups may migrate from the 
oxygen to the nitrogen atom. 

.OH 
/ 



\ 



I^N^C^CHs 



NH2 



This is simply an illustration of the reaction of an ester with an 
amine to form an amide, except that in the above case the ester 
and the amine groups are located in the same molecule. 

Differentiation between the Various Classes of Amines. — 
A. Primary, secondary, and tertiary amines may be differentiated 
by a combination of the acetyl chloride and the isonitrile tests. 



R— NH, 4- 



Cl 
CI 






3K0H 

>■ 



R— K=^C+3 KCH-3 HoO 



62 



QUALITATIVE ORGANIC ANALYSIS 

TABLE XVIII 

Unknown + Acetyl Chloride 



Positive reaction. 

I or II amine 
Heat original amine with CHCI3 and alcoholic potash 



Positive reaction. 
I amine 



No reaction. 
II amine 



No reaction. 
Ill amine 



In this test, the formation of an isonitrile is detected by the 
extremely disagreeable odor that is typical of this class of com- 
pounds. The test is not very satisfactory because it is too delicate 
and consequently most secondary amines, which usually contain 
traces of primary amines, will respond to the test. Exceptions 
are also found, especially among the amines of high molecular 
weight. 

B. Benzenesulfonyl chloride (and other aryl sulfonyl chlo- 
rides) possess an advantage over the usual acyl chlorides of the 
acetyl or benzoyl type in that the sulfonyl derivatives of primary 
amines may be differentiated from the corresponding derivatives 
of secondary amines due to the solubility of the former in alkali. 
This reaction will be discussed further in Chapter XII in connec- 
tion with its apphcation to mixtures. 

Problem 25. — Write the structural formulas for sulfonyl derivatives of 
I and II amines and explain why these derivatives behave differently in 
their reactions with dilute aqueous NaOH solution. 



C. Phthalic Anhydride reacts with many I and II amines very 
readily, even without heating; III amines show no reaction. 



C^ 



R-NH2+ 



o 



o 



c 



./ 



o 



H 

I 
-N-R 



C^OH 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 63 



>NH + 
R/ 






o 



>0 



c^ 

''^ 



\R 
C— OH 



The derivative of the I amine may be differentiated readily 
from the other. When heated sHghtly above its melting-point 
a dehydration reaction occurs with the formation of a product 
no longer soluble in alkali. 



C^^^N-R 



-C^OH 



heat 



/ 



O 



>N-R + H2O 



The reactions of the amines discussed above, with the excep- 
tion of the isonitrile test, are of importance not merely for the 
classification of compounds but also for the preparation of solid 
derivatives and in some instances for the examination of mix- 
tures. Such reactions, which serve simultaneously as classifica- 
tion and as identification reactions, are ideal for the purposes of 
organic analysis. 

The Behavior of Amines Towards Nitrous Acid is also occa- 
sionally of value to differentiate between the three classes of 
amines. In these reactions, primary amines behave somewhat 
differently from the secondary amines. Ammonia also reacts, 
and, indeed, we have here simply an example of the method of 
preparing nitrogen which was studied in inorganic chemistry. 



NH3 + HNO2 



H/H 
HN^O-N=0 
H 



N2 + 2H2O 



Primary aliphatic amines also form nitrites which decompose 
in a manner analogous with the decomposition of ammonium 
nitrite except- that in this instance nitrogen gas and an alcohol 
are formed. This decomposition is not as rapid, however, as one 



64 QUALITATIVE ORGANIC ANALYSIS 

might wish for qualitative tests. When the primary amine group 
is in the alpha position in respect to a carboxyl group, as in many 
of the common amino acids, a very rapid reaction with nitrous 
acid takes place with a practically quantitative evolution of nitro- 
gen gas. The Van Slyke method for the quantitative determina- 
tion of the alpha-amino acids is based upon this reaction. The 
-NH2 group of amides will also react with the formation of an 
acid and nitrogen gas. This reaction is also less rapid than is the 
reaction with the alpha-amino acids. 

Secondary aliphatic amines react with nitrous acid to give 
nitroso derivatives which are practically neutral substances and 
insoluble in water unless the amine is of very low molecular weight. 
Tertiary aliphatic amines do not react with nitrous acid under the 
usual conditions except to the extent of salt formation. 

H 

I /H 
R-NH2 + H-0-N=0 ^ R-N^H -^ N2 + R-OH + H2O 

\0-N=0 

"R T? TT R 

^NH-HH-0-N=0 ;:± ^N^H -> \n-N=0-KH20 

R/ R/ \0-N==0 R/ 

R\ R\ /H 

R^N+H-0-N=0 ;^ R^N< 

R/ R/ \0-N=0 

In the aromatic series, we find that primary amines react 
extremely readily in the cold to form intermediate water-soluble 
products known as diazonium compounds. When the diazonium 
solution is warmed, decomposition takes place with the forma- 
tion of nitrogen gas and a phenol. 



-N< HCl 
\H + HO-N=0 > 



V 



-N2CI heat 
H2O 



)H 

+ N2 + HCl 



These diazonium compounds are extremely valuable in synthetical 
work, since the diazonium group may be replaced with a large 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 65 

variety of other groups, such as CI, Br, I, CN, H, OC2H5, NO2, 
SO2H, etc. These special appHcations of the diazonium com- 
pounds are seldom used in qualitative work since the simpler 
reactions are usually sufficient. 

In addition to replacement reactions, the diazonium com- 
pounds readily undergo coupling reactions with many phenols 
and amines. These reactions, which are of great technical impor- 
tance, are also of value in both qualitative arid quantitative 
organic work. 

Problem 26. — What reagents and conditions are used to replace the 
diazonium group with (a) chlorine, (b) — C=N, and (c) hydrogen? How 
may a diazonium compound be converted into a hydrazine? 

Problem 27. — Write the equations to illustrate the coupling reactions 
of diazonium compounds with phenols and with tertiary aromatic amines. 

Secondary aromatic amines behave as do the corresponding 
amines in the aliphatic series; they form nitroso compounds 
which are neutral substances and only sparingly soluble in water. 
They separate from solution when the amine hydrochloride is 
treated with sodium nitrite solution. Occasionally, when these 
nitroso compounds are solids, they may be used for derivatives. 

The Tertiary Amines. — This class of amines differs from 
ammonia and the primary and secondary amines in its non- 
activity with acyl halides and anhydrides. 

Many amines, including the tertiary type, form double salts 
with such reagents as chloro-platinic acid, picric acid, etc. These 
derivatives are of importance in analytical work in connection 
with identification tests. The formation of picrates, however, 
is not peculiar to the amines; in fact, such derivatives may be 
prepared even from the hydrocarbons of the naphthalene and 
anthracene series. 

Tertiary amines may add alkyl halides and form quaternary 
ammonium compounds which are often solids with definite melt- 
ing-points. The alkyl iodides are usually applied for this purpose. 

R 
R I R' 

R-n/ + R'X -^ R— N<f 
\R I \X 

R 

An important reaction of aromatic tertiary amines consists in 
the formation of nitroso derivatives when the amine salt in acid 



66 QUALITATIVE ORGANIC ANALYSIS 

solution is treated with sodium nitrite. This reaction is typical 
mainly when the para position to the amine group is unoccupied. 

/CH3 
/N< -HCl 

/CH3 X CH3 

-N< HCl (\ 

^CHs + H-0-N=0 > + H2O 



k. 



N=0 



Since in the above reaction-product the nitroso group is on carbon 
and not on nitrogen, we obtain a compound which is still basic 
and thus differs from the nitroso derivatives of aromatic secondary 
amines. The introduction of the nitroso group leads to instability 
of the molecule towards alkah. 

yCHs heat 

CgHs-N^ + NaOH solution > no reaction 

^CHs 

yONa 
/CH3 /\ 

.N< (1) heat f ^ /CH3 



C6H4< ^CHs + NaOH > + H-N 






^N=0(4) solution l^ / ^CHa 

^N=0 

An important class of tertiary amines is represented by com- 
pounds of the pyridine and quinoline types. Although these 
classes are considered as aromatic in character, the basic N 
atom does not add to the ease of substitution into the nucleus. 
These cyclic amines behave more Hke the tertiary aliphatic 
amines since they do not form nitroso derivatives, and they do 
not couple with the diazonium compounds. Addition products 
with the alkyl halides are formed very readily. 

Other Basic Nitrogen Compounds. — The hydrazines, unless 
negatively substituted on the nitrogen, are typical organic bases. 
Phenylhydrazine (CGH5-NH-NH2) is only sparingly soluble 
in water but dissolves readily in dilute HCl. When a second 
aryl group is introduced, 

H H 



<^_i.i_^^^ 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 67 

we obtain a hyclrazo compound which is practically neutral. Hydra- 

H H 

I ^0 1 

zines possessing the structures R-N-NH2 and R-C N-NH2, 

are detected by using benzaldehyde or some other convenient 
carbonyl compound as a reagent. 

Problem 28. — Write the equation for the reaction between (a) vanillin, 
and NHo— NHo, (6) hydrazobenzene and aqueous HCl. 

The diazonium hydroxides are fairly strong bases. These compounds 
and their salts have been discussed in connection with the reactions of 
primary aromatic amines. Although very important in organic work, the 
diazonium compounds are rarely found among the compounds requiring 
identification. This is easily understood when we recall that most of them 
are stable in solution only at comparativeh^ low temperatures. In the 
form of dry solids, most of the salts are highly explosive. 



/^ 



-N=N 



\/ OH \/ 



-N=N-OH 



Benzene diazonium hydroxide 

Quaternary ammonium hydroxides, (R)4:X— OH, are very strong bases 
like the highly ionized inorganic hydroxides. They are seldom met, and 
then usually as chlorides or sulfates. They are manipulated best in the 
form of platinic chlorides. 

Carbamide (urea) forms salts with one mole of acid (NH2 • CO • NH2 • HNO3), 
but in water solution they are mostly hydrolyzed and the acid may be 
titrated, even with phenolphthalein as an indicator. The enzjTne prepara- 
tion "urease" is convenient for the identification and estimation of urea. 

Amidines, some guanidine derivatives, imino-ethers, etc., are not suffi- 
ciently common to require individual attention here. Oximes, when water- 
insoluble, occasionally give evidence of basic properties by increased solu- 
bility in dilute HCl. 

Problem 29. — Write the equation for the action of sodium hypobromite 
in alkaline solution upon (a) benzamide, and (&) urea. 

Acidic Nitrogen Groups. — When a hydrogen of ammonia is 
replaced by an acyl group of a strong acid (sulfonic acid), an 
acidic amide is formed. A similar result is obtained by intro- 
ducing two acyl groups derived from carboxylic acids, thus 
resulting in the formation of an imide (page 20). An examina- 
tion of the tautomeric (lactam and lactim) formulas for these 
compounds suggests an analogy with the structure of the car- 



68 QUALITATIVE ORGANIC ANALYSIS 

boxyl groups, since here also an -OH group is linked to a carbon 

N- 

which is unsaturated; viz.: -C-OH in place of -C— OH. 

Similarly, there are nitrogen groups which may be considered 
as related to the carboxyl group but which possess the nitrogen 
(tri- or pentavalent) replacing the carbon of the carboxyl; e.g., 



O O 

II and II in place of || 

N-OH =N-OH -C-OH 

Compounds containing these groups are acidic, although in the 
case of oximes, very feebly acidic. They are often met in a dif- 
ferent guise, the above formulas representing simply the " aci " 
form of primary and secondary nitroso and nitro compounds. 
See page 22 and Problem 4. 

Tertiary nitroso and nitro compounds do not exhibit this type 
of isomerism except in special instances in the aromatic series 
when, due to the presence of certain other groups, the derivative 
may exist in the form of a quinone-like compound. 

OH 



N-OH 



The acidic nitrogen groups may be subjected to the same class 
reactions which are used for the neutral nitrogen groups and a 
separate discussion will therefore be unnecessary. 

Neutral or Indifferent Nitrogen Groups. — The four most com- 
mon indifferent nitrogen groups are the nitro, azo, nitrile, and 
amide. The following discussion will deal also with a number of 
other analogous groups that are met only occasionally in ele- 
mentary analytical work. These classes of compounds may be 
arranged conveniently into two sub-groups: 

(a) Easily reducible type, 
(6) Easily hydrolyzable type. 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 69 

The nitro and azo compounds are readily reduced by acid 
reducing agents to yield primary amines. 

R-NC + 6H -> R-N< + 2H.0 

R-N=N-R'+4H -> R-NH2 + R'-NH2 

In the above reductions, the amines are present in the form of 
salts of the inorganic acid used. In the iron reduction method, 
however, where only a very small amount of acid is used as a 
catalyzer, the amines are present mostly as free amines, and for 
this reason in the reduction of fairly volatile substances pro- 
vision must be made to prevent loss either of amine or of the initial 
material. 

The reducing reagents which are commonly used in the labora- 
tory are : 

(a) Tin and aqueous HCl, 

(6) Iron powder and 5 per cent iron chloride and water, 

(c) Zinc and neutral salt solutions, 

(d) Sodium amalgam, 

(e) Stannous chloride in HCl solution, 
(/) Zinc and acid. 

(g) Zinc and alkah. 

As will be seen from the subsequent discussion (see also Problem 
35), the reaction of the medium exerts a great effect upon the 
particular reduction products to be formed. 

Problem 30. — The reducing agents above are given in the order of 
importance for laboratory work in qualitative anal.ysis. Explain how and 
why this order differs in technical manufacturing work. 

Amides and nitriles may be readily hydrolyzed to produce the 
corresponding acids together with ammonia or, in the case of 
certain amides, substituted ammonia. To be sure, the amides 
and nitriles may also be reduced to amines, especially with sodium 
in alcoholic solution; with acidic reagents the hydrolytic reaction 
is, however, the prominent one and the one adaptable for ana- 
lytical purposes. 

^0 acid /^O 

R-C^NH2 + H2O > R-C^0H+NH4X 

acid ^O acid ^O 

R-C=N + H20 > R-C^NH2 — > R-C^OH + NH4X 



70 QUALITATIVE ORGANIC ANALYSIS 

The hydrolysis of amides and nitriles may be conducted not 
only in acid solution but also in the presence of alkali. When 
dealing with substances soluble in water only with difficulty, it is 
customary to use alcohol as a solvent. In the latter instance, in 
connection with acid hydrolysis, the organic acid formed in the 
reaction is partially converted into an ester, whereas ammonia, 
or a substituted ammonia, will be present in the form of a salt 
with the inorganic acid used. When the hydrolysis is conducted 
in the presence of alkali, the organic acid is present as the sodium 
or potassium salt, whereas the amine is liberated and, if volatile, 
may be lost when the reaction mixture is refluxed. Type experi- 
ments are illustrated in connection with the laboratory work, 
page 146. 

Problem 31. — Write the equations for the acid hydrolysis of 

(a) CeHs-NCHa-COCHa, 

/CO— NH. 
(6) CH,<' \C0, 

^CO— NH^ 

(c) CcHs-CO-NH-CH.CO-NH-CeHfi. 



In which reaction is a gas evolved? 

Problem 32. — Write the equations and state the experimental conditions 
for 

(a) the conversion of an amide into a nitrile, 

(h^i the formation of an amide from an ester. 

Problem 33. — Write type formulas for compounds belonging to each 
class listed in Table XIX under Groups A, B, and C. 

Analytical Attack of Indifferent Nitrogen Compounds 

Many of the types in Subgroup A represent colored compounds 
and the few individual members which are not colored when pure 
are often contaminated with colored impurities. The simple 
nitro and azoxy compounds are usually light yellow or cream 
colored, whereas the azo compounds are more highly colored. 
Additional substituents, for example, amine groups, will deepen 
the color of nitro compounds. Many simple nitroso compounds 
are green. 



- 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 71 
TABLE XIX 



Sub-group 


A. 


Sul>group B. 


Sub-group C. 


Easily reduced 


Easily hydrolyzed 


Resistant to reduction and 








hydrolysis 


Nitro 




Amides 


Some negatively substi- 
tuted amines 


Azo 




Nitriles 


Certain imides 


Nitroso 




Imides 


Many sulfonamides 


Azoxy 




Derivatives of aldehydes 


Certain heterocyclic types 


Hydrazo 




and ketones: 

(a) Hydrazones 

(b) Oximes 

(c) Semicarbazones 

(d) Osazones 

(e) Aldehyde amine de- 

rivatives 
(/) Cyanohydrins 
Isocyanates 





If a given unknown containing indifferent nitrogen is a color- 
less compound, it is advisable to apply first the hydrolysis test 
for Subgroup B. On the other hand, colored compounds should 
be subjected to reduction tests before resorting to those involving 
hydrolysis. Often a combination of the two tests is advisable, 
alkaline hydrolysis being resorted to when no definite results are 
obtained by acid hydrolysis. 

With the exception of the nitro and hydrazine compounds, 
practically all of these compounds may be quantitatively analyzed 
for nitrogen by the Kjeldahl method. The nitro compounds 
may, of course, be utilized also in such an analysis following 
slight modifications from the usual method of analysis. 

Discussion of Subgroup A. — The nitrogen compounds in this 
class may all be reduced to amines by means of acid reduction 
methods, but they differ considerably in ease of reduction. Fur- 
ther differentiation within the subgroup may often be made by 
the choice of modified methods of reduction. In many instances 
the order of reduction is as follows: Nitroso, azoxy, nitro, and 
azo, the first being reduced most readily. This order differs, 
however, in regard to the character of the reducing reagent and 
is modified greatly by the solubility of the compound. In order 



V 



72 



QUALITATIVE ORGANIC ANALYSIS 



to hasten the reduction of sparingly soluble compounds, alcohol 
is often added. 

The inter-relation between these compounds is shown in the 
following diagram: 



R-N-0 



2H 



^R-N-O-H 



R-N 



^ 



0/2H 



\ 



O 



2r-n: 



/ 



O 



\ 



b\6H 



r-n-^pr^r-n-^n-r^^r-n-n-r 






H H 



The nitro, azo, nitroso, and azoxy compounds may all be 
reduced to the hydrazo stage by means of zinc dust and alkali in 
the presence of alcohol. In this reaction, however, the azoxy 
compounds may often be differentiated from the azo, due to the 
fact that the former are reduced more readily and upon reduction 
go through the deeply-colored azo stage. 

Many nitroso and nitro groups can be reduced by zinc and 
water in the presence of a small amount of a salt like ammonium 
chloride as a catalyzer to form hydroxylamine derivatives which 
readily reduce ammoniacal silver nitrate.^ The nitroso group 
may be differentiated by oxidation (HNO3) to the nitro stage. 



Problem 31. — What is Liebermann's Nitroso Reaction? 
(191G). 



(Mulliken II, 30 



Hydrazo compounds may be oxidized back to the azo stage 
by passing air into the solution of the compound in alcoholic 
alkali solution. In glacial acetic acid, 30 per cent hydrogen per- 
oxide gradually oxidizes both hydrazo and azo compounds to the 
azoxy compounds. 



Cf. Mulliken II, 32 (1916). 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 73 

Several of the types mentioned in the above table are easily 
affected by treatment with strong acids. This is especially true of 
the hydroxylamine, nitroso, and hydrazo compounds. 

CH3 CH3 

^ H H 9 V + dil. HCl 



<3-N-N-<; 



y 

Hydrazoanisole 



CH3 CH3 

o o 



HCl • H2N-<^ /~\~ /-NHs-HCI 

Dianisidine HCl (pp'-di-amino- 
mm'-di methoxy-dip henyl) 

Problem 35. — What products are formed when aryl nitro compounds are 
reduced with zinc in 

(a) neutral solution, 
(6) alkaline solution, 
(c) acid solution? 
How may a similar variety of products be prepared by electrolytic reduc- 
tion? 

Problem 36. — What is formed when sodium methylate acts as a reducing 
agent on nitrobenzene? Will reduction take place when hydrogen gas from 
a Kipp generator is passed into boiling nitrobenzene? 

In this series of indifferent nitrogen compounds, it is not 
essential, however, that an unknown be limited to one individual 
class before proceeding with the work; the identification of the 
products obtained by reduction or hydrolysis together with the 
physical constants and other properties of the original unknowil, 
will serve to simplify the procedure greatly. 

Problem 37.— In a manner analogous with the explanation of the benzidine 
rearrangement, explain the formation of p-aminophenol from phenyl hydroxyl- 
amine and sulfuric acid. What is the semidine rearrangement? 

Problem 38. — Hydrazo compounds are colorless. Why do the samples 
met with usually possess a yellow color. How can we explain that nitroso- 
benzene is green only when in the liquid or vapor phase? What suggestion 
can be given for the deepening of color when the nitrophenols are converted 
into their salts? 

Discussion of Subgroup B. — With the exception of formamide, 
the common amides are solids with fairly high melting-points and 
usually limited solubility in ether and benzene. The nitriles of the 



74 QUALITATIVE ORGANIC ANALYSIS 

corresponding acids are generally liquids or low-melting solids 
unless several -C^N groups are present. The fact that the 
nitriles may yield amides as intermediate products in their hydrol- 
ysis to acids can serve as a method of differentiation. The 
nitriles will yield ammonia upon complete hydrolysis, whereas 
amides may be derived from primary and secondary amines as 
well as from ammonia. 

The various nitrogenous derivatives of aldehydes and ketones 
are usually detected by the products formed by acid hydrolysis. 
The corresponding carbonyl compounds may be isolated often, 
and sometimes the nitrogenous products as well. By sodium 
reduction many of these compounds yield amines, but this re- 
action is of minor analytical importance. 

Problem 39. — Given the phenylhydrazone of methyl ethyl ketone, 
recover the ketone as such and the phenylhydrazine in the form of its benzal- 
dehyde derivative. 

Problem 40. — Two oximes of benzaldehyde are known. Explain this 
case of isomerism. Do both oximes yield nitriles with acetic anhydride? 
What is the Beckmann Rearrangement of ketoximes? 

Discussion of Subgroup C. — The di- and tri- aryl amines 
(negatively substituted amines) are practically neutral substances, 
and naturally are not affected by the usual hydrolytic treatment. 
Aromatic amines with ortho nitro groups are very feebly basic; 
when heated with alkali, ammonia is gradually liberated. (Cf. 
equations, page 66.) 

The imides are often met among the acidic substances, but 
when the hydrogen of the > NH group is replaced with a radical 
they become neutral. Such compounds, particularly when 
derived from cyclic structures of the phthalimide and saccharine 
types, are hydrolyzed only with difficulty under the conditions of 
the usual experiment. They are placed, therefore, in Subgroup 
C. Their hydrolysis is usually carried out by heating with HCl 
to a temperature of approximately 200° in a sealed tube. The 
sulfonamides, also, are resistant to hydrolysis, and most of them 
may be placed in Subgroup C. They are acidic substances unless 
both the hydrogens of the -NH2 group have been replaced by 
radicals. Certain heterocyclic types, for example, the purine 
derivatives, although possessing the amide structure, are less 
susceptible to hydrolysis because of the greater stability given 
by the ring structure. 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 75 

The Sulfur Compounds 

The main classes of sulfm* compounds to be considered are: 

Thiols (mercaptans and thiophenols), 

Sulfides, including cyclic sulfides, 

Disulfides, 

Sulfoxides, 

Sulfones, 

Sulfinic Acids, 

Sulfonic Acids and derivatives, 

Esters of sulfuric acid, 

Sulfates of organic bases, and 

Sulfite addition-products of carbonyl compounds. 

A glance at the formulas for the above types will emphasize 
the close relationship between oxygen and sulfur; thus the thiols, 
sulfides, and disulfides are analogous with the oxygen compounds, 
alcohols, ethers, and peroxides, respectively. Alcohol-like and 
phenolic types, are found among the thiols just as with the cor- 
responding oxygen compounds. The analogy may be carried to 
additional examples. For instance, carbon oxysulfide and car- 

bon disulfide are related to carbon dioxide: C^=0, C=S, C^^S. 
Related to the carboxylic acids are found compounds in which 
one or both of the oxygens of the carboxylic group are replaced 
by sulfur: 

^O X.S x-O X.S 

R-C^OH, R-C^OH, R-C^SH, R-C^-S-H 

In general, these sulfur compounds possess the reactions of the 
corresponding oxygen compounds plus the reactions conveyed 
by the ability of sulfur to assume valences of four or six. 

In a second type of sulfur compounds, sulfur is found usurping 
the place of carbon ; for example, related in structure to the ketones 
are the sulfoxides and sulfones, and related in structure to the 
carboxyl group are the sulfinic acids. Since sulfur may possess 
a variable valence, it may give rise also to sulfonic acids which 
bear the same relation to the sulfinic acids that sulfuric does to 



76 QUALITATIVE ORGANIC ANALYSIS 

sulfurous. These relationships are indicated in the following 
formulas : 

^O /yO ^O 

R-C^OH, R-S^OH, R-Sf OH 

^O 

Carboxylic acid Sulfinic acid Sulfonic acid 

With the exception of the sulfonic acids and the sulfates, the 
above sulfur compounds are of importance only in a few special 
cases, and a detailed discussion of individual classes is therefore 
inadvisable in an elementary course. The derivatives of sulfonic 
acids, such as the sulfonyl chlorides, amides, and imides are of 
considerable importance in qualitative work. 

Carbon Disulfide possesses the ability to form addition 
products: thus 

S 
//$> alcohol II 

C^S + NaOR y R-0-C-S-Na 

solution 



,_N=C=S 




The former reaction is of technical importance in the manufacture 
of viscose and the latter is valuable both in the laboratory and 
in the industries. A corresponding reaction with phenylhydrazine 
is of value in preparing a derivative of carbon disulfide. 

The Thiols and Sulfides are chiefly liquids with penetrating, 
disagreeable odors. With salts of heavy metals, such as mercuric 
chloride, the former yield salts and the latter double salts. 

R-SH + HgCl2 -> (R-S)2Hg 
R-S-R + HgCl2 -^ R-S-R-HgCl2 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 77 

Those thiols (mercaptans) related to the alcohols are scarcely 
acidic enough to yield stable salts with dilute aqueous alkali, 
while those possessing phenolic properties (thiophenols) dissolve 
in dilute alkali. Certain thiophenols are alkali-insoluble for the 
same reason that certain high-molecular-weight phenols are alkali- 
insoluble. 

The most important reactions for compounds which may be 
considered as derivatives of hydrogen sulfide are the oxidation 
reactions. The usual reagent is either nitric acid or perman- 
ganate. For the oxidation of the sulfides to sulfoxides and sul- 
fones, 30 per cent H2O2 in acetic acid as a solvent is a convenient 
and rapidly acting reagent. The thiols may be oxidized readily 
to the disulfides by any one of several reagents, such as NaOI, 
H2O2, and occasionally by the oxygen of the air. 



R-S-H 


30 


R Sf OH 
^0 


2R-SH 


10 

> 


R-S-S-R + H2O 


R-S-S-R 


50 


2R-S|- OH 
^0 


R-S-R 


10 

> 




II 
R-S-R 




II 
R-S-R 


10 


^0 
R— S^— R 
^0 




II 
R-S-R 

II 






— — > 


fairly stable to oxi( 


II 








Problem 40a. — Write the structural formula for the compound known in 
chemical warfare as " mustard gas." Knowing that the corresponding 
sulfoxide is practically non-toxic, how would you attempt to prevent mustard 



78 QUALITATIVE ORGANIC ANALYSIS 

gas burns in recently exposed tissues? J. Am. Chem. Soc. 42, 1208, 1230, 

(1920). 

The low molecular weight sulfoxides and sulfones like 

O O 

II II 

C2H5-S-C2H5 and C2H0— S— C2H5 

II 
O 

are, as might be expected from their structure, slightly soluble 
in water. The members possessing higher molecular weights, 
however, are only sparingly soluble. The greater solubility of 
the sulfoxides is due probably to a reaction with water and their 

presence in solution as R-S^ — R . 

\0H 
The isothiocyanates are of some importance since a few mem- 
bers are found in natural products. They are broken down by 
acid hydrolysis, as was noted also among the oxygen analogues, 
the isocyanates, to produce primary amines. 

acid hydrolysis 
2CH2=CH-CH2-N=C=S + 2H2O > 

(Allyl isothiocyanate from mustard) rl2oW4 

(CH2=CH-CH2-NH2)2H2S04 + 2C0S 

The most common sulfur compounds met in organic analysis 
are the sulfonic acids. The aromatic members are the most 
important since they are easily prepared and possess important 
technical uses. 

In contrast to the sulfinic and carboxylic acids, the sulfonic 
acids are very highly ionized. As might be expected from their 
structure, they are fairly soluble in water and the lower members 
are therefore isolated usually in the form of salts. Many sulfonic 
acids may be hydrolyzed by heating with 25 per cent to 50 per 
cent sulfuric acid to yield the corresponding hydrocarbons or 
derivatives. The ease of hydrolysis differs with different mem- 
bers, and it appears that those compounds which are sulfonated 
most readily yield sulfonic acids which hydrolyze the most easily. 
Benzene sulfonic acid does not yield benzene except under special 



THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 79 



conditions of hydrolysis. Toluene sulfonic acids hydrolyze with 
less difficulty, and the o- and m-xylene sulfonic acids, faii'ly readily. 



SO3H 

/^/^ HOH + H2SO4 

+ H2SO4 




+ heat 




'CHa 



CH3 



HOH + H2SO4 

> 

+ heat 



— CH3 



+H2SO4 



SO3H 



The sulfonic acid group in phenols and amines may often be 
displaced by halogen in connection with the usual bromine- 
water test. 

Another important technical reaction of the sulfonic acids is 
hydrolysis by fusion with caustic alkaUs. In quahtative work, 
this is of minor importance. 

Probelm 41. — Write the equations for the following reactions: 

(a) Fusion of sodium benzene sulfonate with caustic alkali, 

(6) Distillation of sodium benzoate with soda Hme, 

(c)- Heating of anthraquinone-/3-sulfonic acid with ammonia under 

pressure, 
{d) Fusion of saccharin with caustic alkali. 

As was the case with the carboxylic acids, the sulfonic acids, 
also, may be converted into acyl chlorides and identified as such 
or in the form of the amides. Since sulfonic acids and their salts 
usually crystallize with water of crystaUization, it is important 
that they be dried for some time at 100° before subjecting them 
to the treatment with phosphorus pentachloride. The presence 
of other groups (such as OH, NH2, etc.), which also react with 
PCI5, will be expected to interfere with the preparation of the 
acyl chlorides. 



80 QUALITATIVE ORGANIC ANALYSIS 

Compounds Containing Special Elements. — Many metals are 
met in organic analysis in connection with the examination of 
salts. This part of the subject will require no special treatment, 
however, since the general method of attack consists in identifying 
the organic compound after it has been liberated from its salt. 

The organic basic compounds are often met, of course, in the 
form of their salts with inorganic as well as with organic acids. 
Occasionally an organic compound is found combined with inor- 
ganic material as a double salt. Among the organo-metallic 
compounds, derivatives of magnesium, zinc, mercury, etc., are 
valuable laboratory reagents, although they are infrequently 
met in connection with organic analysis. 

In the pharmaceutical field, organic arsenic, mercury, anti- 
mony, and phosphorus compounds are receiving increased atten- 
tion, and similar examples might be given from other specialized 
lines of applied organic chemistry. An attempt to treat such 
specialized lines is inadvisable here. 



CHAPTER V 

COMPOUNDS WITH UNLIKE SUBSTITUENTS 

The majority of the derivatives of the hydrocarbons (saturated 
and unsaturated) contain more than one substituent, and among 
these poly-substituted derivatives a considerable number contain 
unlike substituents. Among the commoner organic compounds 
this distribution is more equable, however; thus in the Tables 
in Part C, we find listed the constants for about two thousand 
fairly common organic compounds. This number is divided 
approximately as follows: 

I. One substituent, 30 per cent, 
11. Two or more like substituents, 10 per cent, 
III. Two or more unlike substituents, 60 per cent. 

Important classes of compounds which fall in the third sub- 
division are: 

(a) Carbohydrates and their derivatives, 

(6) Amino acids and their derivatives, 

(c) Ureides, and 

(d) Dyes. 

In addition to these specialized types, each solubility group 
will contain other classes of compounds with unlike substituents 
and a part of the present chapter will deal with the possible effect 
of such compounds upon the simplified classification and method 
of analysis outlined in Chapter I. No pretense is made to treat 
the above specialized types except in a general elementary man- 
ner; more advanced texts are already available, dealing with 
analytical work in these respective fields. 

A systematic procedure of analysis might be expected to lead 
to narrowness on the part of the student ; this is too often the case 
in inorganic " ion " analysis. Fortunately, organic analysis can- 
not be narrowed down to an analytical procedure which is inde- 

81 



82 



QUALITATIVE ORGANIC ANALYSIS 



pendent of a thorough knowledge of organic chemistry and of the 
abiUty to use that knowledge; the mixed classes of compounds, 
particularly, will prevent such an occurrence. The present chap- 
ter gives only a glimpse into the field; a region in which each or- 
ganic chemist must develop by practical experience in the special- 
ized line in which he is working. 

CARBOHYDRATES 
The carbohydrates are compounds containing carbon, hydro- 
gen, and oxygen, usually of the composition Cre(H20)„or«-i, w-hich 
contain the sugar or " ose " group either free or in combination. 

H /O ... 

The " ose " group is represented as -C-C — or a structure m equi- 

I 
OH 

librium with this form. 

Formula I represents an aldohexose with the free sugar group; 

Formula II represents a disaccharose of the sucrose type with the 

sugar groups in combination. 



CH2OH 
CHOH 
CH 



CH2OH 
CHOH 
CH 



CHOH 
CHOH O 
H— C-OH 



CHOH 
CHOH O 



CH2OH 
CHOH 
CH 



HO-CH 



CHOH 
CHOH 
H-C 



i 



CHoOH 
I 
CHOH 

CHOH 

I 
CH 

I 

,c- 



o 



CrnOH 



-0 



CHoOH 

I 
CHOH 

I 
CHOH 

I 
CHOH 

I 
CHOH 

I 
H— C-OH 

\h 

I 



II 



COMPOUNDS WITH UNLIKE CONSTITUENTS 83 

The structures in (I) represent what is commonly known as 
the lactone formulas for a sugar ; thus, c?-glucose is known in two 
forms, alpha and beta d-glucose. Either isomer in solution is 
gradually converted into an equihbrium mixture which is repre- 
sented by (I). This rearrangement, known as a muta-rotation, 
is hastened by the addition of a trace of alkali, a fact which is of 
importance in connection with the determination of the specific 
rotation of any sugar possessing the free " ose " group. The 
individual shown in II does not muta-rotate. The aldo sugars, 
although possessing a potential aldehyde group do not give the 
fuchsin-aldehyde test. An exception is noted also in the case of 
chloral hydrate, which compound possesses its aldehyde group 

H ,0H 
in combination with water to produce the structure, -C^ 

The presence or absence of the free sugar group enables a classi- 
fication of compounds into (a) reducing sugars, and (6) non- 
reducing sugars. 

The reducing sugars react readily upon heating with Fehling's 
Solution to give a precipitate of cuprous oxide; the second class 
gives no reaction with this reagent. The non-reducing sugars, 
however, may be hydrolyzed with varying degrees of ease to 
mono-saccharoses which react in the normal manner with the 
Fehling reagent. 



Problem 42. — Explain why a disaccharose, like maltose or lactose, 
Ci2H220n, will react with Fehling's Solution. 

Problem 43. — The formula CeHiaOe represents (o) how many aldohexoses, 
(6) how many ketohexoses? 



Fehhng's Solution may be represented as equivalent to a 
solution of cupric oxide and the reaction may be written 
as follows: 

CH2OH CH2OH 

I I 

(CH0H)4 + 2CuO -> (CH0H)4 + CuaO i 



C=0 C=0 



84 QUALITATIVE ORGANIC ANALYSIS 

The reaction is actually somewhat more complex, not only in 
respect to the reagent ^ but also in respect to the products formed 
from the sugars, since the secondary alcohol groups in the sugar 
acid represented above are also susceptible to oxidation. Never- 
theless, the method is available even for quantitative estimation 
provided that the procedure is carried out in a specified empirical 
manner. 

A more nearly typical reaction of the sugar group is that with 
phenylhydrazine, resulting in the formation of an osazone. The 
first step is exactly analogous with the usual aldehyde and ketone 
reactions. Upon continued heating with phenylhydrazine solu- 
tion, the alpha -CHOH group is oxidized by a molecule of 
phenylhydrazine to produce a carbonyl group, which then reacts 
again with phenylhydrazine to form a double hydrazone, known 
as an osazone. 

CH2OH 



(CH0H)4 C6H5NHNH2 

1 


C=N-N-C6H5 

\h H 




CH2-0H 


CH2OH 


(CH0H)3 C6H5NH-NH2 

1 > 


(CH0H)3 


1 _.._., y 

c=o 

1 


C=N-NH-C6H5 
(b=N-NHC6H5 


C=N-N-C6H5 

\h 1 

H 



* The copper in Fehling's Solution is held in combination by the tartaric 
acid in a form which prevents the precipitation of cupric hydroxide. Upon 
electrolysis of such a solution, the copper travels with the negative ion to 
the cathode. This complex ion is often represented as, 

/O-CH-COaG 
Cu< i 

\O-CH-CO20 

Reaction with Fehling's Solution is not typical of the sugar group; many 
other substances, both organic and inorganic, may reduce Fehling's Solu- 
tion. 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 85 

The various sugars differ in ease of reaction with phenylhy- 
drazine, and consequently the " time test of osazone formation " 
(page 144), is of value in giving information concerning a given 
unknown in this group. The crystalline structure and to a minor 
extent the melting-points of the osazones are also of aid in identi- 
fication work. Easily hydrolyzable non-reducing sugars, like 
sucrose, may yield osazones because of the fact that hydrolj^sis 
gradually takes place under the conditions chosen for the experi- 
ment. Such sugars naturally require a greater time for osazone 
formation. 

Problem 44. — Explain why glucose, mannose, fructose, and sucrose give 
identical products in the osazone reaction. 

The specific rotation is a particularly valuable constant for 
sugars as well as for many of their derivatives. This is of special 
importance for the reason that the usual melting-point test applied 
to poly-hydroxy compounds is somewhat dependent upon the rate 
of heating, and additional physical constants are therefore 
desirable. 

In a few instances, sugars may be isolated in the form of the 
simple hydrazones, but in general these derivatives are too soluble 
in water. By choosing hj^drazines of higher molecular weight, 
benzyl phenylhydrazine, /3-naphthylhydrazine, etc., hydrazones 
may be more readily isolated. Aldoses may be differentiated from 

CH3 

ketoses by the use of asymmetrical hydrazines like C6H5-N-NH2. 
Ketoses yield the typical osazones, whereas aldo-sugars form 
only the colorless hydrazones.^ 

Problem 45. — According to the solubility rules in Chapter 11, would you 
expect a hexose hydrazone to be more soluble than the corresponding osazone? 
Would you expect lactosazone to be more or less soluble than glucosazone? 

In addition to the reactions already discussed, the sugars 
possess other typical reactions of the carbonyl, hydroxyl, and 
ether (acetal) linkages, together with a number of more specific 
reactions. Only a few of these will be mentioned for the reason 
that many of them are of synthetical rather than of analytical 
value. 

1 Weyl, Part I, pp. 471-2 (1911). 



86 QUALITATIVE ORGANIC ANALYSIS 

In connection with other aldehydes, the aldo-sugars may form 
acetal-hke compounds when heated with anhydrous alcohol in 
the presence of a trace of HCl. 

HCl CH2OH 
C6H12O6+CH3OH 



CHOH 

I 
CH 



(CH0H)2 

I 
HC-OCH3 



O 



Methyl hexoside 

This acetal linkage is present in the poly-saccharoses and con- 
sequently these compounds may readily be hydrolyzed to yield 
mixtures of mono-saccharoses. When sucrose is thus hydrolyzed, 
the process is called inversion. Why? 

dil. HCl 
Sucrose + H2O > Glucose + Fructose 

The hydroxyl groups of carbohydrates may be acetylated by 
heating with acetic anhydride in the presence of dehydrating 
agents such as fused sodium acetate or zinc chloride. Aldo- and 
keto-hexoses form penta-acetyl derivatives, whereas disaccharoses 
like sucrose, maltose, and lactose form octa-acetyl derivatives. 

Pentoses, pentosides, as well as polyoses which yield pentoses upon hydrol- 
ysis, readily form furfural, 

CH— CH 

II II /H 

CH C-C=0 

\o/ 

when distilled with dilute mineral acids. This heterocyclic aldehyde may be 
identified as the phenylhydrazone; it may be detected qualitatively due to 
the formation of an intensely colored red dye with aniline acetate solution. In 
quantitative work, pentoses are determined by converting them into furfural 
and estimating the latter either with phloroglucinol ^ or with thiobarbituric 
acid.i 

The pentoses are not fermented by yeast enzymes, whereas most hexoses 
are readily attacked. Alcoholic fermentation has been observed among 
trioses, hexoses, and nonoses, which is in agreement with the equation : 

enzyme 
(CR^O-dx > XC2H5OH + 2CO2. 

» J. Am. Chem. Soc. 38, 2156 (1916). 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 87 

The formula (CeHioOs)! represents the complex carbohydrates 
such as dextrins, starches, and cellulose. A general test for these 
classes as well as the simple carbohydrates already discussed is the 
Molisch color test, which is based upon the colors produced when 
a trace of carbohydrate material is treated with sulfuric acid in the 
presence of a-naphthol.^ 

Starch occurs in the form of granules which differ considerably 
in appearance according to the plant from which it is obtained. 
Microscopic examination is therefore of considerable aid in learning 
the source (potato, rice, corn, rye, etc.). In cold water, the gran- 
ules are insoluble but they swell and burst upon heating and yield 
colloidal starch solutions. Starches give a typical blue color even 
with traces of iodine, but are readily hydrolyzed by diastase to 
dextrins, which no longer respond to this typical test, and finally 
to reducing sugars. Dextrins, as well as starches and cellulose, 
may be hydrolyzed by means of mineral acids to yield reducing 
sugars. 

AMINO ACIDS 

The most common aliphatic amino acids possess the formula 
H 
R-C-CO2H.- They are derived not only from mono, but also 
I 
NH2 

from dicarboxylic acids, and among the members from natural 
products a few are known to possess an amino group on a carbon 
atom other than the a-carbon. Lysine, a, e-diaminocaproic 

H 
acid, NH2-CH2-CH2-CH2-CH2-C-CO2H, is probably the best 

I 

NH2 

known example of the latter type. 

1 MuUiken, Vol. I, p. 26. 

2 The radical R- may be H as in glycocoU; alkyl as in a-alanine, leucine, etc.; 

-CH2OH as in serine; 

— C-CH2- /^\ 

11 ■ . . ^ CH C— CH2- . , . ,. ,. . 

I as in tryptophane, 1 11 as in nistidine, 

^^^N-CH N CH 

H H 

HO—/ y" — CH2- as in tyrosine; 
-CH2-S-S-CH2- as in cystine, etc. 



88 QUALITATIVE ORGANIC ANALYSIS 

Amino acids give deep red colorations with ferric chloride and, 
as would be expected from their relation to ammonia, give a deep 
blue color with solutions of cupric salts. The simple a-amino 
acids are practically neutral in reaction; they may be considered 
as inner salts. 

H H H 

R-C-C^O-H ^ R-C-C-^ or R-C-C^O-N^H 

•I I I Hx I |\h 

NH2 H-N-0 h4N-0— C-C-H 

A h/ II I 

HH OR 

As might be expected from these structures, the lower members, 
like glycocoU and alanine, are very soluble in water but insoluble 
in ether. (Solubility Group II.) Members of higher molecular 
weight fall in Groups III and IV. In general, they do not possess 
definite melting-points. 

With nitrous acid, the a-amino acids react very readily to yield 
nitrogen gas and a-hydroxy acids which usually cannot be isolated 
with ease. An excellent volumetric method for the estimation 
of amino acids is based upon this reaction. ^ 

In the presence of an excess of concentrated hydrochloric acid 
and the calculated amount of NaN02, the chloro derivatives of the 
aliphatic acids are obtained, often in good yield.- The most 
valuable reaction of amino acids for use in the qualitative labora- 
tory is the preparation of acyl derivatives. Valuable reagents^ 
for this purpose are benzoyl chloride, benzene sulfonyl chloride, 
/3-naphthalene sulfonyl chloride, and jS-anthraquinone sulfonyl 
chloride, all of which may be used with aqueous solutions of amino 
acids, since these acyl chlorides are only slowly decomposed by 
water. When benzoyl chloride is used, the product obtained 
may be contaminated with a small amount of benzoic acid, which 
may usually be removed because of its greater solubility in ether. 
The benzoyl derivatives of the amino acids are often rather 
sparingly soluble in ether as is true of many amides. 

The acyl chlorides derived from sulfonic acids possess the 
advantage that the organic acid formed as a by-product is usually 

1 Van Slyke, J. Biol. Chem. 12, 275 (1912); 16, 121-125 (1913). 

2 Z. Physiol. Chem. 31, 119 (1900). 

3 Ber. 35, 3779 (1902); Ber. 33, 3526 (1900). 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 



89 



soluble in water. Benzene sulfonyl chloride is the most common 
reagent of this type used in qualitative work. When the cor- 
responding sulfonyl derivatives are too soluble in water, a high 
molecular weight acyl halide, anthraquinone sulfonyl chloride, 
may be used. 



O 
II 

^\^ ^,^^— SO2CI N-C-CO2H 

+ H I 



/ 



R 



' Hi 






/\ 





H H 

— S02-N-C-C02H 


1 


R 




II 







+ HCl 



Peptides 

The polypeptides are compounds in which the carboxyl group 
of one amino acid has reacted with the amino group of a second 
amino acid to produce an amide structure. 



./ 



O 



H 



./ 



O 



NH2-CH2-C^-OH + CHs-C-C^OH 

I 
NH2 

H 



H 



>N-CH2-C^-— N-C-CO2H + H2O 
H/ I 

CH3 

Glycyl alanine, the compound formed in the hypothetical reac- 
tion above, is called a dipeptide. Continued amide formation with 
additional amino acids would lead to the formation of tri- and 
tetra-peptides, etc. These polypeptides possess in addition to 
the reaction of the amino acids the hydrolytic reactions due to 



90 QUALITATIVE ORGANIC ANALYSIS 

the presence of the amide structure. They are products which 
have not only been prepared synthetically but which have also 
been isolated as intermediate products in the hydrolysis of 
proteins. 

Since the sulfone amides are hydrolyzed less readily than the 
amides of carboxylic acids, we have in benzene sulfonyl chloride 
a reagent not only for the isolation and identification of some of 
these substances but also a means for determining the structure 
of a given product.^ For example, glycocoU and alanine may be 
combined to yield two different products. After reaction with 
benzene sulfonyl chloride and hydrolysis of the resultant products, 
we shall obtain in one instance a glycocoll residue united to the 
sulfonyl radical, whereas in the second instance alanine is obtained 
in the form of its sulfonyl derivative. 



Proteins 

The proteins form the bulk of the nitrogenous contents of 
plant and animal cells. They contain chiefly carbon, hydrogen, 
oxygen, and nitrogen, the percentage of the latter varying between 
narrow limits (15 to 17.5 per cent). Small amounts of sulphur 
are often present, and occasionally also phosphorus. These 
compounds are of very high molecular weight, usually non- 
crystallizable, and in solution are present in the colloidal state. 
They may be hydrolyzed to yield amino acids and other products 
whereas some individuals among the conjugated proteins yield 
also purines and pyrimidine bases, phosphoric acid, and car- 
bohydrates. 

Soluble proteins may usually be precipitated by a variety of 
reagents, and many of them may be coagulated by heating. 
Some of the common salts, like ammonium sulfate, sodium sulfate, 
sodium chloride, etc., serve for " salting out " of many of these 
members in the unaltered condition, while certain acids (picric, 
tannic, phosphotungstic, phosphomolybdic, etc.) serve for their 
removal as insoluble salts. 

In addition to the precipitation reagents, a large variety of 
color-tests is in use for the detection of proteins. (A) In Millon's 
Reaction, the material is treated with nitric acid, in which a small 

1 Ber. 40, 3548 (1907). 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 91 

amount of mercury has been dissolved. Upon heating, the pro- 
tein assumes a red color. (B) Under the formidable name of 
Xanthoproteic Reaction, so-called because of the production of a 
yellow color, we meet a common test for the phenolic group. When 
a drop of nitric acid is placed upon the skin, a yellow stain develops 
which, when washed and treated with alkali, turns to a deep orange. 
(C) The Bu'uet Test is based upon the colors produced (pink to 
bluish) when the protein, in strongly alkaline solution, is treated 
with a very dilute copper sulfate solution. When present in 
urine, albumin may be detected by the nitric acid ring test either 
by the formation of a white zone of precipitated albumin or by 
the heat coagulation test followed by the addition of a drop of 
acetic acid. 

The proteins are usually classified into three groups: 

I. The Simple Proteins yield only alpha-amino acids or their 
derivatives upon hydrolysis: this group comprises albumins, 
globulins, glutelins, prolamines, albuminoids, histones, and 
protamines. 

II. Conjugated Proteins contain the protein molecule united 
with some other molecule in some manner other than as a salt, 
Nucleoproteins, glycoproteins, phosphoproteins, hemoglobins, 
etc., are typical members. 

III. Derived Proteins are formed from the first two groups, 
due to hydrolytic changes. The group comprises proteans, 
metaproteins, coagulated proteins, proteoses, peptones, and 
peptides. 

Further classification of the simple proteins is of interest to 
the student of organic analysis because of the appHcation of sol- 
ubility behavior for the classification of this group of complex 
natural products, viz.: 

Simple Proteins: 

1. Albumins. Soluble in water but coagulated by heat. 

2. Globulins. Insoluble in water but soluble in neutral 

salt solution. 

3. Glutelins. Insoluble in neutral solvents but soluble in 

dilute acids and alkali. 

4. Prolamines. Insoluble in water but soluble in 70 per 

cent alcohol. 

5. Albuminoids. Insoluble in all neutral solvents. 



92 QUALITATIVE ORGANIC ANALYSIS 

6. Histones. Soluble in water but precipitated by am- 

monia. 

7. Protamines. Soluble in water but not coagulated by 

heat. 

For analytical work m tnis special field, the advanced texts 
referred to at the end of the chapter should be consulted. 

AROMATIC AMINO ACIDS 

Many amino acids derived from aromatic acids differ appre-i 
ciably from the aliphatic type because of the feeble basicity of 
the amine group. In general, these compounds possess definite 
melting-points and appreciable solubility in ether. Since the 
amino group is very feebly basic (page 20), these acids may 
usually be titrated in the presence of phenolphthalein and a 
fairly accurate neutral equivalent obtained. A specific example 
will be treated below in the general discussion of compounds 
containing several reactive groups. 

In addition to derivatives of aromatic carboxylic acids, a large 
number of amino derivatives of aromatic sulfonic acids is known. 
Many of these compounds are of importance as dye intermediates. 
Due to the presence of the sulfonic acid group, they are no longer 
ether-soluble. Many of the members are of fairly high molecular 
weight and hence of limited solubility in water. Acids of this 
type, together with phenolic sulfonic acids and compounds, 
which possess both the phenolic and the amino groups, are met in 
commerce under names such as the following: H acid, F acid, 
Gamma acid, G salt, R salt, Broenner's acid, Cleves' acid, 
Neville and Winther's acid, etc. 

A few of the commoner members are known by names which 
are more suggestive of their structure, such as sulfanilic acid, 
metanilic acid, naphthionic acid, etc. 

THE UREIDES 
O 

Urea, NH2-C-NH2, is the amide of carbonic acid. It may be 
condensed with various acids to produce substituted amides which 
are known as ureides. In addition to these simple compounds, 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 93 

several groups of cyclic ureides are of importance, particularly 
the purines, pyrimidines, and hydantoins. 

Ni=6CH N=CH HN— CH2 

I 1 H II I 
H-C2 5c— N\ HC CH 0=C 

II II >C-H8 II II I 
N3— 4C— N9^ N— CH HN— C=0 

Purine Pyrimidine Hydantoin 

Although the mother substances, purine and pyrimidine, are not 
themselves important, many of their derivatives occur in natural 
products. Only a few can be mentioned here. 

2, 6-Dihydroxy purine Xanthine 

2, 6, 8-Trihydroxy purine Uric Acid 

2, 6-Dihydroxy-3, 7-dimethyl purine Theobromine 

2, 6-Dihydroxy-l, 3-dimethyl purine Theophylline 

2, 6-Dihydroxy-l, 3, 7-trimethyl purine Caffeine 

6-Hydroxy-2-amino purine Guanine 

These compounds exhibit typical reactions which may be pre- 
dicted according to their structures; some of them, however, 
possess unusual stability towards hydrolysis when compared with 
the simple urea derivatives. Such variations in stability are no 
doubt associated with the stabilities of the heterocyclic structures. 
Thus, the purines or pyrimidines may be considered as possessing 

/^\ 

C C 

a nucleus, || | , which in some respects is comparable with 

N C 

the benzene nucleus. Hydantoin, on the other hand, when heated 
with dilute alkali, readily hydrolyzes to hydantoic acid and then 
into ammonia, carbon dioxide, and glycocoll. It is feebly acidic, 
as might be expected from the imide structure, and appreciably 
soluble in water, as might also be predicted from its structure, and 
the melting-point of 216°. 

Uric acid is a fairly strong acid; it dissolves readily in dilute 
alkali, and is precipitated from alkaline solution in the form of a 
sparingly soluble acid-salt by means of carbon dioxide. It is 
fairly resistant towards hydrolysis. Caffeine, on the other hand, 



94 QUALITATIVE ORGANIC ANALYSIS 

possesses no acidic hydrogen but is feebly basic, as might be ex- 
pected from its structure. Heating with alkali results in hydro- 
lytic action. 

Problem 46. — Predict the products formed when creatinin 

H-N— C=0 

I 
HN=C 

I 
CHs-N— CH2 

is subjected to hydrolysis by boiling in alkaline solution. 

An important test often applied to the purine derivatives in 
order to differentiate them from other amides is the murexide 
reaction. A small quantity of the compound (1/100 g.) is 
moistened with a few drops of 1/1 HCl. A minute crystal of 
KCIO3 is added and the mixture evaporated on a crucible cover 
upon the steam-bath. A pinkish or yellowish color is usually 
apparent at this stage, and this color deepens upon gentle warm- 
ing of the residue over a free flame. After cooling, the reaction 
product is moistened with a drop of ammonia water, which 
results in the production of a purplish color. ^ 

Nitrogen determinations by the Kjeldahl method are impor- 
tant in connection with the identification of compounds of this 
type. 

ALKALOIDS 

The alkaloids are basic compounds possessing at least one 
heterocyclic nitrogen atom. These compounds, many of which 
exhibit powerful physiological action, occur generally in certain 
plants. The term alkaloid is often applied, however, in a broader 
sense so as to include compounds of the purine and pyrimidine 
types which occur in the animal body as well as in plants. Many 
members of the latter type are not basic but, like uric acid, are 
really acidic compounds. A still broader classification might 
include many other nitrogenous compounds, natural as well as 
synthetic (adrenalin, novocaine, etc.), which do not contain 
heterocyclic nitrogen atoms but which exhibit physiological 
behavior suggestive of the vegetable alkaloids. 

In general, the alkaloids possess a variety of unlike substitu- 
ents although certain members are relatively simple and may be 

1 Ber. 30, 2236 (Suppl.); Mulliken, 2, 31. 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 95 

considered as substituted hydrocarbons possessing only one or 
two reactive groups. For example, coniine behaves exactly Hke 
other secondary amines, nicotine is relatively more complex, 
whereas in atropine we have an example of the presence of a 
variety of unlike groups in the same molecule. 

/CH2\ CH2 — CH2 

II 

CHo CH2 //\ Att /.tt 

I I r^\ 9^' 

CH2 CH-CH2CH2CH3 I \N/ 

\ / ^N^ I 

\^/ CH3 

JT Nicotine 

Coniine 

CH2 — CH CH2 

I I 

N-CH3 CH-O-CO-CH-CeHs 

I I I 

CH2— CH CH2 CH2OH 

Atropine 

Problem 47. — Point out the asymmetric carbon atoms in the formulas 
for coniine, nicotine, and atropine. Are the natural products optically 
active? 

What is formed when coniine is subjected to exhaustive methylation? 
(Ref. Stewart, Recent Advances in Organic Chemistry, 1918, pp. 125-6.) 

Such compounds, even when a considerable number of unlike 
substituents is present, will occasion no special difficulty. The 
well-known members, including a few the structures of which are 
not known with certainty, are included in the tables for common 
organic compounds given in Part C. 

The reason for a specialized treatment of alkaloids in most 
schemes of analysis is not due to any unusual variation from the 
reactions predicted for the substituents present but because of the 
powerful physiological action of many individual members. Be- 
cause of the latter reason, the compounds are often met in 
extremely minute quantities, as for instance, in connection with 
the toxicological examination of animal tissues. In such instances, 
the methods of microanalysis are frequently of value. 

Since alkaloids often occur in minute quantities, classification 
based upon color reactions with various alkaloidal reagents is 
generally used. The individual members may sometimes be 
detected by means of their typical physiological behaviors. 



9t) QUALITATIVE ORGANIC ANALYSIS 

For work in this field, the larger texts must be consulted, par- 
ticularly the special treatises upon the subject. References are 
given at the end of this chapter. 

ORGANIC DYES 
The common classes of organic dyes are the following: 

f Monoazo, 
(1) AzoDyes: \ Di-azo, 

I Tri-azo, etc. 

Malachite green series, 



(2) Triphenylmethane 
Dyes: 



Rosaniline series, 

Auramines or Rosolic acid series, 

Phthaleins, Rhodamines, and Eosines, 

f Pyronines, 



(3) Diphenylmethane , . ... 
^ ' _ < Acridmes, 

I Auramines, 

I Anthraquinone type (Indanthrenes), 

(5) Anthracene dyes of the alizarin type, 

(6) Nitro and Nitroso dyes, 

(7) Sulfur dyes (Sulfide colors, Thiazines, etc.), 

Indamine, 
Indophenols, 

(8) Diphenylamine Dyes: i Thiazine, 

Oxazine, 
. Safranines. 

Problem 48. — As an exercise, the student should write the formulas for 
various dyes found in the above classes. He may limit himself to the specific 
classes which are studied in his general course in organic chemistry. 

Problem 49. — Give a list of (a) the common chromophore groups, (6) 
the common auxochrome groups. 

The examination of organic dyes, particularly because of the 
large number of individual compounds and mixtures ordinarily 
met in technical products, is work for the specialist. Attempts 
have been made toward the systematic grouping of dyes based 
upon chemical reactions. Thus the scheme of Rota^ is based 
iChem.Zeit. 1898,437. 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 



97 



upon the behavior of dyes towards various reducing and oxidizing 
agents. Rota has suggested the following classification: 

TABLE XX 

Unknown in 1 : 10,000 Solution (Water or Alcohol) 

Treat with dilute HCl and SnClo 



Reduction to colorless solution. 
Neutralize and add FeCls. 


No reduction by SnCl2. 

To original solution add 20 7o KOH 

and warm 


Color not restored 
Class I 


Color restored 
Class II 


Decolorization or 
precipitate 

Class III 


No precipitation 
and color deep- 
ens 
Class IV 



Further discussion of this scheme of classification and the 
methods used for subdivision of the four main classes is not justi- 
fiable in the space available here. 

Effective work in connection with the identification of dyes 
usually requires also actual dyeing experiments. A particularly 
valuable physical property which is utilized in connection with the 
identification of dyes is the absorption spectrum of dye-solutions. 

A more recent and far more extensive treatment for the identi- 
fication of dyes has been developed by Mulliken. Identification 
of Pure Organic Compounds, Vol. III. About fifteen hundred 
dyes are classified in this extended treatise. The method of 
attack is as follows: 

(1) Homogeneity test (a) water, (6) sul- 
furic acid, (c) fractional dyeing, 
(d) capillary absorption, (e) spec- 
troscopy, 

(2) General appearance and color, 

(3) Solubilities in water, alcohol, sul- 
furic acid, 

(4) Tests for sulfur dyes, 

(5) Direct dyeing of wool and cotton, 

(6) Dyeing with hydrosulfite vat, 

(7) Dyeing with sodium sulfide vat. 



Preliminary Tests: 



98 



QUALITATIVE ORGANIC ANALYSIS 



Generic or Divisional 
Tests: 



Coordination Tests: 



(8) Discharge of direct wool dyeings by- 
sodium formaldehyde sulfoxylate, 

(9) Restoration of color by air, 

' (10) Restoration of color by potassium 
persulfate, 
(11) Color discharges and returns on vat- 
dyed cotton. 

f Action of H2SO4 on textile dyeings, 
Action of NaOH on textile dyeings. 
Action of nitrous acid on wool dyeings. 



Special Tests: 



Precipitation tests — H2SO4, NaOH, sulfates of 

Ca, Cr, Cu, and tannin, 
Dyeing on mordanted wool, 
Diazotization and -development with /3-naphthol, 
Reduction products of azo dyes. 
Absorption spectra. 



Verification test and use of color standard. 



The scheme proposed by Mulliken naturally finds more or less 
criticism from the specialists in the dye industry. No doubt much 
valuable information has been developed in the research labora- 
tories of the dye works but only a limited amount of such data 
becomes public property. The technical worker who is most 
prolific in his criticism is usually the one who is most secretive 
with his own results. 

The particular dyes which are permitted by the U. S, Govern- 
ment in foods and beverages have been limited to ten.^ These 
have been selected because they are relatively harmless; they 
may be readily manufactured in the pure condition; and they 
may be readily identified. ^ These colors, which are also met in 
the form of mixtures, may be classified as follows: 

Red shades 

107. Amaranth, 
56. Ponceau 3R, 
517. Erythrosine. 

1 U. S. Dept. of Agriculture, Decisions Governing Colors in Food. 

2 Leach, Food Inspection and Analysis. 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 99 

Orange shade 

85. Orange I. 
Yellow shades 

4. Naphthol yellow S, 
94. Tartrazine, 

Yellow A.B. (Benzenazo-/3-naphthylamine) m. 103°, 
Yellow O.B. (Ortho-toluenazo-/3-naphthylamine) m. 
126°. 
Green shade 

435. Light green S.F. yellowish. 
Blue shade 

692. Indigo disulfoacid. 

The numbers preceding the names refer to the numbers of the colors as 
hsted in A. G. Green's edition of the Schultz-JuHus Systematic Survey of 
the Organic Coloring Matters, published in 1904. 

An important reaction of the azo dyes consists in their reduc- 
tion to the corresponding amino compounds. An important 
reagent for this purpose is stannous chloride in hydrochloric acid 
solution. In this reduction, compounds are broken between the 
two nitrogens of the azo group and from the resultant simpler 
compounds, the structure of the original dye may often be deduced. 

Problem 50. — An azo dye upon reduction yielded benzidine, p-amino- 
dimethylaniline and l-amino-2-hydroxynaphthalene on reduction. What is 
the structure of the dye and what products serve as intermediates for its 
manufacture? 

Problem 51. — What are the indanthrene dyes? (Ref. Stewart, Recent 
Advances of Organic Chemistry, 1918, p. 6.) 

EFFECT OF POLY-SUBSTITUTION 

In the discussion of chemical reactions, we have for the most 
part considered simple type compounds. Several examples have 
been met which demonstrate that the simultaneous presence of 
several substituents may lead to a modification of the usual 
reactions. The present section will summarize some of the 
examples already discussed and will offer additional illustrations 
from the standpoint of possible effect upon the proposed scheme 
of analysis. 

In Chapter II, we noted the fact that the -NH2 group in an 
organic molecule may be basic, neutral, or even acidic ; the par- 
ticular behavior towards ionization depends upon the group joined 



100 QUALITATIVE ORGANIC ANALYSIS 

to the amine nitrogen. Groups which when substituted into the 
molecule lower the basicity of a base or increase the acidity of an 
acid are often spoken of as negative groups. It is not essential 
that the negative group be directly joined to the amine group. 
Aniline is a weak base but substitution by the nitro group decreases 
the basicity still farther. Meta and p-nitraniline are only feebly 
basic but there is no doubt but that they fall in solubility Group III. 
A nitro group in the ortho position, however, exerts a still greater 
effect and we find o-nitraniline and 2, 4-dinitraniline to be almost 
insoluble in dilute acids. Halogens exert an effect similar to, but 
less powerful than, the nitro group. The substitution of three 
halogen atoms into aniline jaelds a compound that is only feebly 
basic. 

The union between carbon and nitrogen is fairly stable towards 
hydrolysis; negative substitution, however, leads to instabihty. 

R— NH2 > heat 

I + alkali > No reaction. 

Ar-NH2 J 

/NHsO) heat /OH(i) 

CeHK + alkali > CeH^ +NH3 

^N02(2 or 4) \N02(2 or 4) 

Nitro groups exert a similar effect upon the labilization of 
halogen, the effect being greatest in the ortho position. 

/CI 

ale. sol'n No reaction unless at 

+ alkali + heat > very high temperature 

under pressure. 

CI /ONa 



— NO2 

+ NaCl + HoO 



NO2 

+ 2NaOH 4- heat 



The union between carbon and carbon is generally very stable 
and is ruptured only by high-temperature reactions. We have 
already observed, page 43, however, that in the structure 

O O 

II II 

-C-CH2-C- 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 101 

we can readily disrupt the union between carbon and carbon. 
This is true also when a carbon atom adjacent to the carbonyl 
is heavily substituted by halogen. 

CAC-C^H + aq. NaOH -> CHCI3 + H-C^ONa 
CK 

Ac-C^CHs + aq. NaOH -* CHI3 + CH3C02Na 
\/ 

Carboxylic acids do not readily lose carbon dioxide except at 
high temperatures or when fused with caustic. When two car- 
boxyl groups are joined to the same carbon atom, one molecule of 
carbon dioxide is readily lost: 

R\ /CO2H heat to 

>C< > R-CH2CO2H + CO2 

W \CO2H about 150° 

Dicarboxylic acids with the two carboxyl groups in the a, /3 or 
a, 7 positions readily undergo anhydride formation when heated 
either alone but preferably with dehydrating agents. Such reac- 
tions are expected when the substituent groups are in positions 
favoring formations of 5- or 6-atom cyclic structures. 

Problem 62. — Illustrate the formation of succinic, maleic, and phthalic 
anhydrides. What is produced when calcium glutarate is subjected to a 
high temperature? / 

A reaction analogous with that of cyclic-anhydride-formation is 
the formation of lactones from 7-hydroxy acids and from 7-halo- 
gen acids. (Cf. page 39.) A related reaction is the dehydration 
of acids possessing a carbonyl group in the gamma position. 



P OH . ^ 

CH3C-CH2CH2CO2H- CH'3C=CH-CH-2C02H^^^ CH3C=CH-CH2C=0 +H2O 



Levulinic acid \h^c;CH2CH2C02H^^CHiC-CH^CH2CO+H,0 



i — ' 

Problem 53. — According to the theory of geometrical isomerism, one of 
the above lactones may exist in two forms. Explain this case. 



102 



QUALITATIVE ORGANIC ANALYSIS 



a-Hydroxy acids and a-amino acids may also form anhydrides 
but in such instances two molecules of the substituted acid (or 
derivative) are concerned. 



H 



O 



2CH3-CHOH-CO2H 



2NH2-CH2-C^OR 



CH3— C— C^O 



O— C— C-CH3 + 2 H2O 

II I 
O H 



CH2-C^^jj 
\C CH2 

II 
o 



+ 2R0H 



a-Hydroxy acids are readily decomposed when heated with 
sulfuric acid, to yield carbon-monoxide and a carbonyl derivative. 
The formation of an unstable a-lactone structure, by dehydration 
reaction, is probably responsible for this behavior. By analogous 
reaction, oxalic acid is expected to furnish equal volumes of carbon 
monoxide and carbon dioxide. 



R OH 

\ / 

/- 



// 







OH 



^x A'/ 

C-;c 

R 



R 
-> C=0-l-CO 
R 



Problem 54. — /3-Lactones are usually utistable and break down to yield 
carbon dioxide and an ethylene derivative. Write the equation for such a 
reaction. 

The hydrolysis reaction of 1, 3 diketones have already been 
considered. The 1, 2 diketones in the aromatic series when heated 
in alkaline solution show an interesting reaction — the rearrange- 
ment to hydroxy acids. 

C<^ /OH 

C^COaNa 
NaOH 




\y 




COMPOUNDS WITH UNLIKE SUBSTITUENTS 103 

Problem 56. — Write the equation for the reaction of 1, 2 diphenyl-ethane- 
dione-1,2 with concentrated alkaU. What is the name for this rearrange- 
ment? 

Problem 56. — What is the pinacone-pinacolin rearrangement? 

Although this treatment of the behavior of poly-substituted 
compounds is necessarily limited, sufficient material has been pre- 
sented to show that these so-called complications are not such in 
reality, but instead are of considerable aid in analytical work; 
even the present superficial treatment of the subject may have 
served to suggest that these apparent exceptions are fairly general 
among themselves and therefore may be utilized for further sys- 
tematization of the work. 



BEHAVIOR OF POLY-SUBSTITUTED COMPOUNDS IN CONNEC- 
TION WITH IDENTIFICATION WORK 

The question concerning possible complications introduced in 
the scheme of analysis by the occurrence of compounds possessing 
two, three, or four substituents will be treated with a few examples, 
presenting, however, only a part of the usual laboratory data. 

(a) The formula, CeHs^-O — C— R, represents an ether, an 
\CO2H 

ester, and a carboxylic acid. The preliminary tests will probably 
detect only the acidic group and this will place the compound in 
Group IV, but until we have proof to the contrary we shall consider 
the possibility of the simultaneous presence of any number of indif- 
ferent groups. The relatively high neutral equivalent (above 200) 
suggests the possibility that indififerent groups are present. We 
may therefore test for the presence of such groups, remembering, 
however, that the acidic group known to be present may compli- 
cate our tests slightly. In applying a phenylhydrazine test, for 
example, we shall consider the possibility of precipitation of a 
hydrazine salt. The most common tests to which we shall sub- 
ject such unknowns, in addition to tests with Br2 water, FeCla, 
etc., are attempts at hydrolysis with alkali or acid. Since the 
unknown is soluble in dilute alkali, the alkaline solution is refluxed 
for a short time. Acidification precipitates an acid but melting- 
point and neutral equivalent show that the original substance has 



104 QUALITATIVE ORGANIC ANALYSIS 

undergone hydrolysis, and the change in neutral equivalent tells 
us the molecular weight of the group that has been eliminated. 
Moreover, the recovered acid in contrast to the original unknown 
now shows phenolic characteristics. 

With these facts, together with the physical constants, v/e are 
now prepared to turn to the classified tables of Group IV (or to 
the larger reference books if necessary) and plan additional work 
for the conclusive proof of identity. 

/CO2H 
/ gy 
(6) The compound, C6H2 q_qtt > is insoluble in water but 

soluble both in dilute alkali and dilute acid; we shall laler look for 
the compound in both Solubility Groups III and IV. Other indif- 
ferent groups may also be present. Since nitrogen is present, the 
acidic group might prove to be acidic nitrogen, but since the 
compound yields a reasonable value for neutral equivalent (and 
a sharp end-point in titration) we provisionally assume the pres- 
ence of a fairly strong acidic group like carboxjd. 

Bromine is present as shown by analysis, and boiling the solu- 
tion of the unknown in dilute alkali fails to remove halogen. 

Because of its basic nature the compound is tested with acetic 
anhydride. Since the reaction product is insoluble in dilute acid, 
we conclude that the unknown is either a I or II amine, but the 
sulfonyl chloride test in this case will not differentiate between 
these two classes. Why not? Attempted hydrolysis b}^ boiling 
in both acid and alkaline solution (why may aqueous instead of 
alcoholic solutions be used?) indicates the presence of a substance 
stable towards hydrolysis. 

With this information at hand, we may now consult the tables 
listing compounds in Groups III and IV, and plan subsequent 
specific tests. A direct proof of the presence of -OCH3 will 
probably be unnecessary. Kjeldahl analysis for nitrogen might 
have aided in the earlier stages of analysis as well as in presenta- 
tion of final evidence, 



COMPOUNDS WITH UNLIKE SUBSTITUENTS 105 

REFERENCES 

Carbohydrates 

J. B. Cohen: Organic Chemistry for Advanced Students, 

E. F. Armstrong: The Simple Carbohydrates and Glucosides. 

Abderhalden: Handbuch der Biochemischen Arbeitsmethoden. 

Allen: Commercial Analysis, Vol. I. 

C. S. Hudson: Publications in J. Am. Chem. Soc. 

Amino Acids and Derivatives 

R. H. Plimmer: The Chemical Constitution of the Proteins. 
P. B. Hawk: Practical Physiological Chemistry. 
Hammarsten-Mandel : Physiological Chemistry. 
E. Fischer: Untersuchungen liber Aminosauren, Polypeptide, und 

Proteine. 
T. B. Osborne: The Vegetable Proteins. 
Abderhalden: Biochemisches Handlexicon. 

Lehrbuch der Physiologische Chemie. 

Ureides, Alkaloids, etc. 

A. Pictet-Biddle: The Vegetable Alkaloids. 

T. A. Henry: The Plant Alkaloids. 

A. W. Stewart: Recent Advances in Organic Chemistry. 

E. Fischer: Untersuchungen in der Puringruppe. 

S- Frankel: Arzneimittel Synthese. 

P. May: Chemistry of Synthetic Drugs. 

Allen: Commercial Analysis, Vols. V and VH. 

N. V. Sidgwick: Organic Chemistry of Nitrogen. 

Dyes 

Cain and Thorpe: The Synthetic Dyestuffs and Intermediate 

Products. 
G. Schulz: FarbstofTtabellen. 
O. Lange: Die Schwefel Farbstoffe. 
H. Bucherer: Lehrbuch der Farbenchemie. 
S. P. Mulliken, Vol. HI. Identification of Organic Compounds. 
E. R. Watson: Colour in Relation to Chemical Constitution. 



106 QUALITATIVE ORGANIC ANALYSIS 

A. G. Perkin: The Natural Organic Colouring Matters. 
U. S. Gov't Bulletin: Census of Dyes and Coal Tar Chemicals for 
1920. 

General 

H. Sherman: Organic Analysis. 
A. E. Leach: Food Inspection and Analysis. 
G. Lunge: Chemisch-technische Untersuchungsmethoden. 
J. Lewkowitsch: Chemical Technology and Analysis of Oil, Fats, 
and Waxes. 



PART B 
LABORATORY DIRECTIONS 



CHAPTER VI 

PROCEDURE FOR THE ANALYSIS OF AN INDIVIDUAL 

COMPOUND 

Solubility reactions are made the basis for dividing organic 
compounds into a definite number of groups. In the case of an 
unknown substance, the elementary analysis, as well as the 
physical properties of the compound, will still further narrow 
down the number of possibilities. In order to decide definitely 
to which homologous series a certain compound belongs, it is 
necessary next to apply class reactions, i.e., homologous tests. 
The unknown should be subjected to those homologous tests, and 
only those, which are justified on the basis of the solubility reac- 
tions and the elementary analysis; it is only in this manner that 
qualitative organic analysis can receive a logical treatment. 
Finally, when the homologous series to which the unknown belongs 
has been located, the physical properties of the compound will 
locate the individual within this series. It is desirable, however, 
to follow the above procedure by a confirmatory test which con- 
sists in the preparation of one or more simple derivatives and a 
determination of the physical constants of the latter. 

Chapter I should be re-read before proceeding with the 
identification work. 



107 



108 QUALITATIVE ORGANIC ANALYSIS 

OUTLINED METHOD OF ATTACK 

The suggested steps in a systematic procedure for the identi- 
fication of an individual organic compound are: 

1. Physical examination, 

2. Determination of constants, 

3. Elementary analysis, 

4. Solubility tests, 

5. Homologous tests, 

6. Consultation of literature, 

7. Preparation of derivatives. 

1. Physical Examination. — Examine the unknown for homo- 
geneity, color, odor,^ crystalline structure, etc., after a careful 
purification, if the compound is not pure when obtained. Observe 
the behavior of the substance in the ignition test. (Exp. 1, page 
122.) If the substance burns readily or leaves a carbonaceous 
residue, it may be considered as organic. A few common organic 
compounds rich in oxygen or nitrogen (urea, formic acid, etc.), do 
not burn readily. Test any residue after ignition for alkalinity 
and if appreciable in amount, thus indicating more than a trace of 
impurity, examine it by the usual qualitative inorganic method. 
Carefully record these observations but do not be misled or 
prejudiced in your subsequent work by preliminary observations. 
The color of the unknown may be due to the presence of traces of 
impurities, particularly of oxidation products; an apparently 
typical odor may prove to be due to a mere trace of an odoriferous 
impurity. 

2. Determination of Constants. — Determine first the melting- 
points of solids and the boiling-points of liquids. In many instances, 
both constants may be determined and, if so, this is highly desir- 
able. From the behavior of solids in the ignition test, determine 
whether a melting-point determination is advisable. Usually, 
with salts it is necessary to determine the constants of the free 
organic compound after liberation from the salt. Certain organic 
hquids decompose upon distillation, and for this reason any vis- 

' The taste of certain organic compounds is occasionally of value to the 
analyst but because of the obvious danger involved this test should never be 
applied at this stage of the analysis when the nature of the compound is 
entirely unknown. 



THE ANALYSIS OF AN INDIVIDUAL COMPOUND 109 

cous-appearing liquid should be tested (how?) before attempting 
to distil the sample. 

A specific gravity determination is especially valuable for 
liquid unknowns (page 118). The weighed sample should be 
reserved for use in a later test where a weighed amount of material 
may be required. 

Other physical constants, such as refractive index, optical 
rotation, semi-quantitative solubility determinations in solvents 
of different types, etc., are reserved until later in the course 
of analysis, since their application may possibly prove unnec- 
essary. 

3. Elementary Analysis. — Analyze the unknown for carbon, 
nitrogen, halogens, sulfur, and metallic residue left upon ignition. 
(See Chapter VII for details.) A test for hydrogen is unnecessary. 
Tests for special elements — phosphorus, arsenic, lead, mercury, 
etc., are not applied as a routine procedure in this course but when 
such tests are necessary they will be suggested in connection with 
Steps 4 and 5. In applied work, the source of the material or the 
usual information concerning the use for the substance under 
examination is usually of value in suggesting the advisability of 
testing for special elements. 

Quantitative analj^ses for any characteristic element is occa- 
sionally applied in connection with the final identification in Step 7. 
(See Chapter XI.) As a general rule, it is advisable to titrate 
any alkaline residue left upon ignition in order to differentiate 
between traces and appreciable amounts of alkalinity. 

4. Solubility Tests. — Determine the solubility of the unknown 
in water, dilute alkali, dilute acid, ether, and cold concentrated 
H2SO4. For details and discussion see Chapters II and VIII. 
Finally consult the Solubility Table at the end of this text. 

5. Homologous Tests. — Prepare a list of homologous series 
to which the compound might belong, drawing your conclusions 
from the solubility reactions, the elementary analysis, and the 
physical properties of the compound. Allow for the presence of 
indifferent groups (including unsaturation) not specifically detected 
in the solubility tests. 

Apply homologous tests for those types (and only those) 
which are included in your list of possibilities. Suggestions for 
this work are obtained not only from the experimental work in 
Chapter IX, but also from Chapters III, IV, and V. 



110 QUALITATIVE ORGANIC ANALYSIS 

6. Consultation of Literature. — After the application of class 
reactions, the compound may be limited to a very small numbei 
of homologous series and often to one homologous series. At this 
stage, but not before, should the table of physical constants be 
consulted. If the unknown is not found in these tables listing 
several thousand of the simpler substances liable to be encoun- 
tered then the larger reference books, such as Mulliken and Rosen- 
thaler, must be consulted. 

7. Preparation of Derivatives. — Apply confirmatory tests by 
preparing one or more characteristic derivatives (Chapter X) 
and determine the physical constants of these derivatives. A color 
reaction, although of value as an indication, cannot be accepted 
as a confirmatory test. Neutral equivalents, saponification 
equivalents, volatility constants of certain aliphatic acids, and 
quantitative estimation of groups, are occasionally equivalent 
to a derivative. Usually one typical derivative is sufficient but 
the amount of confirmatory work will depend upon the require- 
ments for the differentiation between the individual compounds 
that are accepted as possibilities after completion of the work in 
the preceding six sections. 

LABORATORY NOTES 

Record all observations directly into your laboratory note- 
book and do this in the order in which tests are made as directed 
in the procedure above. The conclusion drawn from any observa- 
tions and the process of reasoning involved should also appear 
in the note-book, and will be of assistance to enable the instructor 
to offer helfpul criticism. The most important object in a begin- 
ning course in organic analysis is not so much the correct solution 
of a given unknown which is the invariable result when com- 
paratively simple unknowns are met, but the manner in which the 
conclusion is derived. The student is not limited to the above 
procedure in connection with all of his identification work in the 
laboratory. In fact, he is asked to apply the directions only to 
the first three simple unknowns, after which he is urged to study, 
apply, and compare the procedures for identification as given in 
other manuals, such as Clarke, Mulliken, and Rosenthaler. 



CHAPTER VII 

DETERMINATION OF PHYSICAL CONSTANTS AND 
ANALYSIS FOR THE ELEMENTS 

The steps essential to a systematic and successful identification 
of an individual organic compound have been outlined briefly in 
the preceding chapter. The term pure organic compound has been 
intentionally avoided, since the analyst seldom meets such indi- 
viduals. 

The identification work in connection with this course will 
consist of the identification of six or eight individual compounds 
and subsequently some experience will be offered also in connec- 
tion with the separation of mixtures. (Chapter XII.) Some of 
the individual compounds may, however, require purification; 
it will be advisable never to assume unreservedly a high degree of 
purity but to approach each problem in an unorthodox attitude 
and draw every conclusion in accordance. In this course " con- 
stant boiling-points " and " sharp melting-points " will not be 
taken as absolute criteria of purity; such constants justify sub- 
mission of the unknown to the regular identification procedure 
but subsequent tests (solubility, class reactions, preparation of 
derivatives, etc.), will provide the necessary supplementary evi- 
dence regarding purity. An actual example taken from the labora- 
tory will illustrate this point. 

A given unknown ^ appeared to be pure since the boiling-point 
was fairly constant at 198°-199° while preliminary examination 
and solubility test gave no indication of a mixture. By means of 
the usual systematic tests the unknown was limited to the class of 
primary aromatic amines, and consultation of the tables (page 
200) suggested the following individual possibilities: 

^ The sample was purchased on the market as o-toluidine of special purity. 

Ill 



112 



QUALITATIVE ORGANIC ANALYSIS 



B.p. 



199° 
200° 



203° 
205° 



o-Toluidine Acetyl Dcr. m. 112° Benzoyl Der. m. 142° 

p-Toluidine 

m.p. 42° Acetyl Der. m. 148° Benzoyl Der. m. 158° 

7w-Toluidine Acetyl Der. m. 65° Benzoyl Der. m. 125° 

^Menthylamine 

Since p-toluidine is a solid, it appeared to be excluded from the 
list of possibilities. However, the acetyl derivative of the unknown 
melted at 120° after one crystaUization and at 146-7° after the 
second and subsequent purifications. This agreed with the value 
for the acetyl derivative of p-toluidine; consequently a benzoyl 
derivative was prepared. It was found to melt at 157° and the 
mixed melting-point with known benzoyl-7>toluidine showed an 
unchanged value. The difficulty was easily explained in the light 
of these numerical data. The unknown, although of constant 
boiling-point, was a mixture of toluidines, the solid para compound 
being dissolved in the liquid ortho isomer. The acetyl derivative 
was a mixture, but after several crystallizations from water the 
more soluble ortho compound was removed and pure acet-p- 
toluidine remained. 

Manipulation of Small Amounts of Material. — When prelim- 
inary work indicates that an unknown is of questionable purity, it 

will be necessary to subject the com- 
pound to additional purification. 
Solids may usually be subjected to 
crystallization from suitable sol- 
vents, and liquids to fractionation. 
Distillation with steam, sublimation, 
and fractional precipitation are also 
occasionally of value. The methods 
used in previous organic laboratory 
work can therefore be applied but 
with suitable modifications to adapt 
the procedures to manipulation of 
relatively small amounts of material 
in such a way as to prevent mechani- 
cal losses. 

In general, it is necessary to 
use miniature apparatus. Many 
of the operations ordinarily requir- 
ing a separatory funnel can be 
carried out efficiently (see Fig. 3), by means of the suction pipette. 




<-^ 



© 



Fig. 3. 



DETERMINATION OF PHYSICAL CONSTANTS 



113 




Fig. 4. 



The latter is made by drawing out one end of an ordinary 
thin-walled glass tube and fire-polishing the 
ends. It should be *of about 2 cc. capacity, 
graduated at ^ cc. intervals, and equipped 
with a piece of narrow gum tubing of suffi- 
cient length that the tip of the pipette may 
be held at eye-level during the manipulation. 
The suction pipette is used not merely for 
separating liquid layers but also for measuring 
definite amounts of liquid organic reagents 
used in various tests. The method of pour- 
ing a portion of unknown or of an organic 
reagent from a test-tube or bottle and 
guessing at the quantity of material used, 
results not merely in a waste of material 
but also in poor results. Solid reagents are 
weighed on micro-platform or on horn-pan balances which permit 
rapid weighing with an accuracy of about 0.02 g. 

For suction filtration, particularly 
when the liquid is to be saved, the 
apparatus shown in Fig. 4 is of 
value. 

Fractionations of small amounts 
of liquid that require a fractionating 
column are often very troublesome. 
The combined flask and column 
shown in Fig. 5 will often solve such 
a difficulty. 

The examples given above will 
suggest a few of the directions in 
which effective work involving small 
quantities of material may be con- 
ducted without serious losses; ex- 
cellent directions for the manipula- 
tion of small amounts of material in 
connection with the preparation of 
derivatives will be found in Mulli- 
ken. Vol. I. When only extremely 
small quantities of material are avail- 
able, resort must be had to the methods of micro-analysis. 




114 QUALITATIVE ORGANIC ANALYSIS 

I. MELTING-POINTS 

The ignition test will determine the advisability of taking a 
melting-point. Obviously it will be a waste of time to attempt 
taking melting-points on compounds which show no evidence of 
melting definitely when heated on platinum-foil. Most salts of 
acidic organic compounds with metals do not possess definite 
melting-points and the constants of the members which do melt 
before undergoing decomposition are not always available in the 
literature. Many hydrochlorides of organic bases possess reliable 
melting-points, but in general this class of compounds shows too 
little variation in melting-points among the individual members. 

Compounds of high molecular weight often undergo decompo- 
sition before melting, and others may sublime. Many compounds 
undergo appreciable decomposition at temperatures near the 
melting-point and therefore the value obtained may vary some- 
what with the rate of heating. This is noticeable with certain 
dicarboxylic acids (which ones?) and especially with polyhydroxy 
compounds, as with the sugars and some of their derivatives. A 
few types show two melting-points. Explain how this is possible. 

A sharp melting-point is not necessarily a criterion of purity. 
A more reliable criterion is obtained by fractionally crystallizing 
a compound from two solvents of widely different types and 
redetermining melting-points of the various fractions. Small 
amounts of fusible impurities usually lower the melting-point.^ 

Mixed Melting-points are of Special Value in Qualitative 
Organic Analysis. — A small amount of the substance to be tested 
is intimately mixed with an equal portion of the known compound 
and the melting-point determined. If the two samples are iden- 
tical, the melting-point will be unchanged, whereas the mixing of 
two different compounds possessing the same melting-point will 
usually, but not invariably, result in a different and usually a 
lower melting-point.^ 

The melting-point of a crystalline substance is that tempera- 
ture at which the solid is in equilibrium with the liquid phase. 
The melting-points usually determmed in the organic laboratory 
(and this is true also of most of the values recorded in the literature) 
are not true but capillary melting-points. 

iFor exceptions, see C. A. 14, 57 (1920); also Finlay: The Phase Rule 
and Its Applications. 



DETERMINATION OF PHYSICAL CONSTANTS 



115 



A small quantity of finely powdered solid material is placed in a 
capillary tube, ^ Fig. 6, and heated in a sulfuric acid or oil bath as 
indicated in Figs. 7 and 8. The open beaker method using a 
stirrer is preferable. The part of the capillary tube containing 
the substance should lie in contact with the bulb of the thermom- 
eter. As the temperature of the bath approaches the melting- 
point, the substance will often sinter and shrink from the walls of 
the tube; occasionally softening is noted as the melting-point is 



Fig. 6. — Actual Size. 





approached; finally the material liquefies, sometimes gradually'' 
over a range of several degrees but more often quite sharply. 
For example, a given unknown was observed to soften at 138°, 

^ A light-walled glass tube 15 mm. in diameter is heated uniformly over 
about 3 cm. of its length and drawn out into meter lengths of uniform bore. 
The capillaries are then cut into convenient lengths, sealed at one end and 
protected from contamination by storage in a dry stoppered test-tube. For 
a determination of melting-point a 5 mm. layer of material is placed in a tube. 
Vibration of the latter by means of a file will be of aid in causing the material 
to settle rapidly to the bottom of the tube in a compact layer. 

When a sulfuric acid bath is used, the capillary tube (if of imiform bore 
and of sufficient length as shown in Fig. 6) will adhere to the thermometer 
by capillary attraction. When an oil-bath is used, a small rubber band may 
be used to fasten the capillary. 



116 QUALITATIVE ORGANIC ANALYSIS 

actual liquefaction was noted at 142° and the substance was com- 
pletely melted at 142.5°. It is customary to record these data in 
the following manner: m.p. 142-142.5° c. (softens at 138°). The 
letter c indicates that the thermometer reading has been corrected ^ 
for stem exposure. 

In general, it is advisable to make two determinations; in the 
first one the bath may be raised quite rapidly and the melting- 
point located within a range of about 5°. The bath is then 
allowed to drop 10°-20° below the melting-point, a new charged 
capillary tube attached to the thermometer, and the temperature 
of the bath raised gradually and uniformly (stirring). As the 
actual melting-point is approached, the temperature of the bath 
should be raised at the rate of about 1° per five to ten seconds. 

Question: A sample of o-phthalic acid was found to melt at 185 "-lOS" 
when the capillary tube was placed in the cold bath and the temperature 
gradually raised to the melting-point. The bath was then allowed to cool 
to 175° and the melting-point of a second portion determined. The second 
value was found to be 200°-205°. Explain these variations. 

For melting-point determinations in the neighborhood of 300", 
it is advisable to use either (a) a sulfuric acid bath containing about 
40 per cent of potassium acid sulfate or (6) a cotton-seed oil bath 
containing about 10 per cent of beeswax. In all work of this kind 
even at low temperatures, particularly where sulfuric acid is used, 
special precautions must be observed to prevent accidents. The 
work at the higher temperatures must be conducted under a hood. 

Many organic compounds that are met in the form of liquids may 
be solidified by chilling in a freezing mixture. In such cases true 
rather than capillary melting-points are determined. A 1 or 2 cc. 
portion of the liquid is placed in a test-tube and a thermometer 
placed directly in the liquid. The tube is then placed in a freezing 

^ The formula often used is: Correction = +N(< — /')0 000154; in which 
N represents the number of degrees on the stem of the thermometer from the 
surface of the bath to the temperature read, / the temperature read, I' the 
average temperature of the exposed mercury column, and 0.000154 the 
apparent coefficient of ex-pansion of mercury in glass. 

Since this correction is of questionable accuracy under the usual labor- 
atory conditions, it is advisable for each student to calibrate a 360° thermom- 
eter against a standardized laboratory thermometer. The two instruments 
are placed side by side in the bath shown in Fig. 7 and comparisons made 
over the entire temperature range at 25° inter\'als. It is essential in this 
case to use a slightly larger bath and also a stirrer. 



detehmination of physical constants 117 

mixture and the walls of the tube scraped with the tip of the ther- 
mometer. Very often persistent supercooling will be noted but 
after a compound has once been solidified an accurate melting- 
point value may be determined, 

II. BOILING-POINTS 

The usual method of determining boiling-points when appre- 
ciable amounts of liquid are available is to actually distill a 5-10 cc. 
portion of the material. This procedure furnishes not merely a 
boiling-point but also something of more value in ordinary work, 
namely, a boiling-point-range. The operation differs from the 
usual distillation procedure only in the use of smaller amounts of 
material and miniature apparatus. 

The small 10 cc. flask is placed upon a square piece of asbestos 
board which contains a perforation of about 2 cm. diameter. A 
small flame is used so as to prevent superheating, but care must 
be taken to prevent fluctuations in the thermometer reading due 
to variable cooling of the vapors in the neck of the flask. The bulb 
of the thermometer should be placed near the outlet of the flask 
and naturally the temperature reading is not taken until the 
mercury of the thermometer has been given time to come to the 
temperature of the vapor. Because of the small amount of liquid 
distilled it is necessary to distill slowly. The type of condenser 
used (air or water-cooled) depends upon the boiling-point of the 
liquid being distilled, but should be of small size so as to prevent 
excessive loss of the distillate. Very high-boiling liquids may be 
collected directly into a test-tube receiver since the quantity of dis- 
tillate is so small. When some suggestion is at hand in regard 
to possible decomposition upon distillation, it is necessary to test a 
cubic centimeter of material by heating in a small test-tube before 
subjecting the main portion of the sample to a high temperature. 

Substances which boil with decomposition under ordinary 
pressure may usually be distilled under diminished pressure. 
Usually this will not be necessary when dealing with an individual 
compound since other constants and particularly the constants of 
derivatives may be relied upon. For the separation of certain 
liquid mixtures which contain ingredients that may be distilled 
only under reduced pressure, it is necessary to resort to this modi- 
fied method. 



118 



QUALITATIVE ORGANIC ANALYSIS 



!^ 



The boiling-points of small portions of material (about I cc.) 
may be determined in the apparatus shown in Fig. 9. The test- 
tube and attached thermometer are heated in the usual melting- 
point bath equipped with a stirrer. The test-tube contains a 
glass tube, 4 mm. in diameter, which acts as a condenser; the 

lower end (8 mm.) is sealed off but is 
open at the end and immersed to a 
depth of about 4 mm. in the liquid 
under examination. The bath is heated 
to slightly above the boiling-point of 
the unknown until the last traces of 
air have been driven from the lower 
open end of the condenser tube. As 
the temperature of the bath is now 
slowly lowered it is noted that vapor 
bubbles cease to emerge from the lower 
end. Soon after this, the liquid tends 
to slowly draw back into the tube. 
The temperature at which the level 
of the liquid within the tube is the 
same as that outside is taken as the 
boiling-point; i.e., the temperature at 
which the liquid is in equilibrium with 
the vapor. 

In the hands of the beginner, the 
method described above is not par- 
ticularly reliable and it is therefore 
necessary to test out the apparatus on 
several compounds of known boiling- 
points before relying upon the results obtained with unknown 
compounds. The method i» adaptable only to work with pure 
compounds and is therefore of limited value. 



m 




Fig. 9. 



III. SPECIFIC GRAVITY 



The density of liquid unknowns is determined most conveni- 
ently by means of the specific gravity tube ^ shown in Fig. 10. 
The tube is standardized by weighing it, first empty and again 

^ These tubes are easily prepared by sealing one end of a thick-walled 
glass tube of 3-mm. diameter and blowing a bulb of the form shown. 



DETERMINATION OF PHYSICAL CONSTANTS 119 

after it is filled with distilled water and the level of the latter 
adjusted to the mark at a temperature of 20°. The dry tube 
should be kept in a clean box with a card showing (a) its weight 
filled with water at 20°, and (6) its weight when empty. In all 
subsequent work one filling and weighing will be sufficient to 
determine the specific gravity of the unknown. 

In determining the specific gravity of an unknown, fill the tube 
to slightly above the etched mark by means of a glass tube drawn 

to a capillary of such diam- ^ ^^ 

eterthat it may be inserted ( ' (i () 

through the narrow neck 

to the bottom of the tube. Fig. 10.— Actual size for tube of about 

Place the tube and its con- 0.6 cc. capacity. 

tents in an upright position 

into a small beaker containing water at 20°. After ten minutes, 

adjust the level of the liquid to the reference mark by means of 

the capillary pipette, dry the tube, and weigh it. The specific 

.,20. 

gravity (aoo) will be equal to the weight of the sample divided by 
the weight of the same volume of water. Weighings are taken 
only to the third decimal place. ^ 

Before returning the tube to the box, the liquid is recovered by 
withdrawing it with the capillary pipette and the tube is cleaned 
first with alcohol and with ether. Finally, the ether vapor is 
removed by drawing, not blowing, air through the pipette. 

OTHER PHYSICAL CONSTANTS 

Melting-point, boiling-point, and specific gravity represent the 
three constants of organic compounds that are determined as a 
routine procedure. Other constants, such as refractive index, 
optical rotation, quantitative solubility determinations, etc., are 
applied in later stages of an analysis if found to be of sufficient 
importance to aid in the differentiation between a number of pos- 
sibilities. Molecular weight determinations are required only 
in exceptional instances. 

The Index of Refraction (n) is the ratio of the sine of the 
angle of incidence to the sine of the angle of refraction (ratio of the 

' Greater accuracy is not justified because of the questionable purity 
of many unknowns. A temperature of 20° has been chosen not only because 
it is near room temperature but also because many of the results in the liter- 
ature have been reported at 20°. 



120 QUALITATIVE ORGANIC ANALYSIS 

velocity of light in air to that in the substance under examination) ; 
it may be read directly by means of the Abbe refractometer, which 
is the most convenient form of instrument for use in the quahta- 
tive laboratory. 

The Specific Rotation of an optically active compound is 
determined by means of the polariscope. The specific rotation 

a observed by sodium light at the temperature t is calculated 
according to the formula : 

100 a 



H> 



IXc 



where a represents the observed angle of rotation (either + or — ), 
I the length in decimeters of the column of liquid in the polariscope 
tube, and c the number of grams of active substance in 100 cc. of 
solution. 

Molecular Weight Estimations may be made by a variety of 
methods, the most important of which are the cryoscopic, the 
ebullioscopic, and the vapor density methods. The first mentioned 
method, based upon the accurate determination of the depression 
of the freezing-point of a known solvent following the introduction 
of a known weight of solute, is generally applicable and is used most 
often by the organic chemist. The molecular weight {M) is cal- 
culated according to the formula: 

A 

where c is a constant for the particular solvent used, p is the num- 
ber of grams of the unknown per 100 g. of solvent, and A is the 
depression of the freezing-point. A similar formula is used for 
calculation of molecular weights based upon the elevation of the 
boiling-point of a liquid due to the presence of a non-volatile dis- 
solved substance. In the latter instance, the constant c' is sub- 
stituted for c and A now represents the rise in boiling-point. 

In connection with the identification of organic compounds 
that have been previously characterized, the estimation of equiva- 
lent weights is of more value that that of actual molecular weights. 
This is done by estimating quantitatively some typical element or 
reactive group. Such methods are discussed in Chapter XI. 

The Value of Physical Constants when Used in Connection 
with Class Reactions. — Unnecessary group tests are often applied 



ANALYSIS FOR THE ELEMENTS 121 

by the beginner when the desired specific information may be 
gained from a consideration of the physical constants of an 
unknown. Examples will be given from among the halogen 
derivatives of the hydrocarbons but similar applications may be 
made to other classes of compounds. 

When a halogen compound possesses a boiling-point below 
125° at 760 mm., the unknown cannot be an aromatic compound. 

When an organic bromine derivative boils below 150°, it 
must be aliphatic. Similarly, an iodine derivative with a boiling- 
point below 180° must be aliphatic. In these instances, sulfona- 
tion and other tests for differentiation between the aliphatic and 
aromatic series are superfluous. (Note that the above statements 
are not limited merely to halogen derivatives of hydrocarbons, but 
apply to all organic halogen compounds.) 

When an organic chlorine derivative boils below 175° but 
possesses a specific gravity of more than 1.4^0°, then it is an ali- 
phatic compound; similarly, bromine compounds boiling below 
200° but possessing specific gravities of more than 1.6-^° must 
be aliphatic compounds. 

Explain the statements given above and be prepared to cite evidence 
either for or against these generalizations. Why would it be unsafe to base 
analogous statements upon melting-point data? 

ANALYSIS FOR THE ELEMENTS 

Test the unknown for an inorganic residue by igniting a small 
amount of material in a crucible. If a residue is left, examine 
it by the usual methods used in inorganic qualitative analysis. 
Residues from calcium and barium salts will be detected readily. 
Sodium and potassium salts will leave fusible residues of the cor- 
responding carbonates which may be overlooked by a careless 
observer. Some inorganic materials may prove to be volatile 
(give examples), whereas others may leave black residues of either 
oxide or reduced metal (give examples). Usually, however, 
black residues are due to the presence of carbonaceous matter 
which is removed only upon prolonged heating. 

Many fairly pure compounds leave a trace of residue upon 
ignition and in cases of doubt this may be weighed in order to 
determine whether it represents an appreciable portion of the total 
weight. 



122 



QUALITATIVE ORGANIC ANALYSIS 



ANALYSIS FOR S, N, CI, Br, AND I 

Very few organic compounds contain these elements in such a 
form that they may be tested directly by the methods of ion analy- 
sis; fusion with metallic sodium, however, decomposes the organic 
substance according to the following scheme : 

heat 
[C, H, O, N, S, CI, Br, I, etc.] + Na^ > 

Na2S, NaCN, NaCl, NaBr, Nal, Na20, C, CO2, H2O, etc. 

In the fusion mixture, sulfur may therefore be detected by the 
usual tests for sulfide ions, nitrogen by the tests for cyanide, and 
the halogens by the usual familiar methods. 
Rarely, when sulfur and nitrogen are both 
present, a trace of NaCNS may also be 
formed and may be detected by the red 
coloration given with ferric chloride after 
acidification. 

Directions for the Sodium Decomposition. 
— Place a piece of clean metallic Na the size 
of a very small pea into a 2-inch test-tube 
suspended through a piece of asbestos board 
as shown in Fig. 11. Add a little of the 
material (one drop of a liquid or a few frag- 
ments of a solid) and heat the tube with a small 
flame, not only until the sodium melts, but 
until the vapors of sodium form a layer | inch 
in height. Allow three drops of the unknown, if 
liquid, or an equivalent quantity of fragments, 
if solid, to fall at intervals of one or two seconds 
directly upon the fused sodium without 
touching the sides of the tube. (Precaution!) Heat the reaction- 
mixture strongly so as to oxidize most of the residual sodium as 
well as to remove volatile organic decomposition products. By 
means of a pair of tongs, lower the hot tube into a small beaker 
containing 10 cc. of water. (Special precaution!) The tube is 
merely touched to the surface of the water and then raised out of 
the liquid but held in the beaker in such a manner that the heavy 
glass of the beaker will be between the tube and the ej^es of the 
operator. Momentary contact with water will cause the hot tube 



¥ 



Fig. 11. 



ANALYSIS FOR THE ELEMENTS 123 

to crack and traces of unreacted sodium will be destroyed by spon- 
taneous burning without the dangers of a hydrogen explosion. 
(Demonstration by instructor.) The cooled tube is now tapped 
against the inner side of the beaker and the lower cracked part 
allowed to drop into the water. The solid particles are broken 
up with with a stirring rod, the solution heated to boiling and fil- 
tered. The filtrate, which should be colorless, is reserved for the 
subsequent tests. 

A. Sulfur Test. — To 1 cc. of the filtrate made slightly acid 
with acetic acid, add a few drops of lead acetate reagent. A 
black precipitate of PbS shows the presence of sulfur. 

B. Nitrogen Test. — Boil 3 cc. of the alkaline stock solution 
for two minutes with 5 drops of FeS04, and 1 drop of FeCls solu- 
tion. Cool and acidify carefully with HCl. The precipitate of 
iron hydroxide should dissolve readily, otherwise the solution 
should be warmed very gently. A clear yellow solution indi- 
cates a negative nitrogen test; a blue precipitate indicates a posi- 
tive test. A blue or greenish-blue solution suggests the presence 
of nitrogen but indicates that the original sodium decomposition 
may have been poor. The precipitate of Prussian blue shows up 
best when it is collected and washed upon a white filter paper. 
If iodine is present, the filter is washed with alcohol to dissolve 
out the iodine. In the presence of sulfides, it wiU be advisable 
to add enough FeSOi solution to completely precipitate the sulfur 
ions, filter off the FeS, and proceed as above. 

Write equations illustrating the formation of Prussian blue. 

C. Tests for Halogen, (a) General Test. — Acidify 2 cc. of 
the stock solution with dilute HNO3 and boil well to expel any 
HoS or HCN if present. Add AgNOs solution. A precipitate 
denotes the presence of halogens. Also apply the Beilstein copper- 
oxide-wire test to the original unknown. 

(6) Tests for Bromine and Iodine in the Presence of Each 
Other and the Other Halogens. — Acidify 2 cc. of the stock solution 
with H2SO4 and boil gently to drive off H2S. Add not more than 
J cc. of carbon tetrachloride and finally a drop of a solution of 
freshly prepared chlorine water. Shake after the addition of each 
drop. If iodine is present, the carbon tetrachloride will be colored 
purple. Continued additions of chlorine water will cause the 
iodine color to disappear, due to the formation of the iodate, and 
if bromine is present the carbon tetrachloride will become colored 



124 QUALITATIVE ORGANIC ANALYSIS 

brown at this stage. Be careful to add the chlorine water slowly 
or these colors may be missed. 

(c) Tests for Chlorine in the Presence of Other Halogens. — 
Acidify 2 cc. of the stock solution with a few drops of acetic acid, 
add excess of Pb02, and boil gently until all the Br2 and I2 are 
liberated. Dilute and test for CI by the addition of HNO3 and 
AgNOs. A faint chlorine test may be due to a trace of chlorine 
either in the metallic sodium or in the glass of the test-tube used 
for the fusion, or in the Pb02. A blank test should be run. 

Beilstein CuO Test for Halogen. — This test is apphed to the 
original unknown. A copper wire of small diameter is heated in 
the flame until no trace of green color is noted. The cooled wire is 
dipped into a small portion of the substance and again heated. A 
green color imparted to the flame, sometimes only a momentary 
flash, is due to the volatilization of copper halide. 

The above tests are the only ones appUed in a routine way to the unknowns 
met in the present course. Carbon and hydrogen may be detected by heat- 
ing the substance in a dry test-tube with ignited CuO and identifying the 
moisture and carbon dioxide generated. Such a test is usually superfluous, 
since abundant amounts of elementary carbon may be observed in the sodium 
decomposition reaction, and special tests for hydrogen are unnecessary for 
the purposes of identification of unknowns . 

Phosphorus may also be detected in the filtrate from the sodium decom- 
position, provided that a 1 cc. portion of the filtrate be oxidized by boiling 
with a little concentrated nitric acid and subsequently tested with ammonium 
molybdate reagent. A more reliable test which is applicable also to quan- 
titative work consists in fusing the organic compound (if non-volatile) with 
sodium carbonate and a small amount of potassium nitrate in a nickel cru- 
cible. The melt is dissolved in acid and tested with molybdate reagent in 
the usual manner. 

The Carius sealed tube method is capable of yielding excellent results but 
is ill-suited to routine work because of the time factor. In special instances, 
however, it may be necessary to apply the method which with slight modi- 
fication is applicable to the quantitative as well as qualitative estimation 
of a variety of elements. A sample weighing 0.1 gram is heated in a sealed 
bomb tube with 1 cc. fuming nitric acid (sp. g. 1.48) at a temperature of 
200-300° during several hours. Sulfur, arsenic, and phosphorus are con- 
verted into sulfuric, arsenic, and phosphoric acids respectively, chlorine and 
bromine will be present partly as hydrochloric and hj^drobromic acids and 
partly as free halogen, iodine as iodic acid, and metals will be present as 
nitrates. Because of considerable pressure developed, great care must be 
taken not only in heating but especially in opening the bomb-tube. The 
detailed directions in Gattermann's Laboratory Manual should be studied 
carefully before undertaking this dangerous operation. 



ANALYSIS FOR THE ELEMENTS 125 

A satisfactory method for treatment of organic arsenic consists in digestion 
with sulfuric acid (in the presence of starch) by analogy to the Kjeldahl 
method for nitrogen. Qualitatively the arsenic may be detected as sulfide 
and quantitatively by iodimetric methods. (J. Chem. Soc. 109, 1356 (1916)). 
The Marsh test serves for the detection of traces of arsenic. 

Mercury in organic combination may often be converted into inorganic 
form by digestion with hydrochloric acid, filtration from insoluble impurities 
and precipitation with hydrogen sulfide. See also Whitmore: Organic Com- 
pounds of Mercury, A. C. S. Monograph, pp. 361-367 (1921). 

For references concernmg these and other specialized tests the list men- 
tioned at the end of Chapter V should be consulted. 



CHAPTER VIII 

LABORATORY WORK ON THE SOLUBILITY BEHAVIOR 
OF ORGANIC COMPOUNDS 

The analytical procedure presented in this course has been 
systematized primarily on the basis of solubility behavior. Before 
proceeding with the application of the scheme, it is advisable to 
devote one or two laboratory periods to the study of the solubility 
behavior of known compounds and to the comparison of predicted 
solubility values with those actually determined experimentally. 

Determine the solubility behavior of a number of typical 
organic compounds, selecting members from various important 
homologous series. (A suggested list is indicated on page 129.) 
Test the solubilities in the following reagents: 

1. Water. 

2. Ether. 

3. Dilute acid (5 per cent HCl).i 

4. Dilute alkali (5 per cent KOH). Note odor of evolved 

gases. 

5. Cold concentrated H0SO4 ^ (if the compound is insoluble 

in tests 1, 2, 3 and 4). 

Solubility tests are applied at room temperature (20°-25°). 
Observations of value may be made by determining solubility 
behavior in hot solvents but for purposes of classification the 
results obtained at room temperature arx the ones desired. The action 
of hot acid or alkali will be studied subsequently in connection 
with the homologous tests. 

Amount of Material Required in Solubility Tests. — The quan- 
tity of the unknown used in a solubility test will naturally depend 
upon the amount available. Usually it is convenient to use 0.10 g. 

1 Tests applied to any evolved gases are also of value. Caution must be 
observed since poisonous products like hydrocyanic acid, carbon monoxide, 
and cyanogen may occasionally be encountered. 

126 



THE SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 127 

of a solid ^ or 0.2 cc. of a liquid for 3 cc. of solvent. The same 
portion of substance may be used, however, in several solubility 
tests and occasionally practically the entire quantity of material 
may be recovered for use in subsequent work. When a particu- 
larly rare substance is under investigation, correspondingly smaller 
amounts of substance and solvent must be used and special 
thought be directed to the question of recovery. 

Solubility in Water and in Ether. — A 0.10 g. portion of a solid 
unknown is treated with successive 1 cc. portions of water until 
3 cc. have been added. If the compound does not dissolve in 
the ratio of 1 : 20 or 25, it is designated " insoluble in water." 
The substance if solid must be finely powdered so as to eliminate 
the possibility of a verdict of insoluble when in reality a mechanical 
difficulty is responsible for the decision. If the substance appears 
to be insoluble, the suspension may be warmed gently. If solu- 
tion occurs, the test portion is again cooled and shaken vigorously 
to prevent supersaturation upon cooling. 

When dealing with liquid unknowns, 0.2 cc. of the substance, 
delivered from the graduated pipette, is added to 3 cc. of water. 
In this case equilibrium is attained quickly and the substance is 
called insoluble if it does not dissolve in the proportion of 1 : 10 
or 15. The student should not be misled, however, by the presence 
of a trace of insoluble impurity in an otherwise soluble substance. 
Give a theoretical explanation justifying a different standard of 
solubility for solid in comparison with melted compounds. 

■ Whenever a compound dissolves in water, test the aqueous 
solution with litmus paper. In the case of liquids that are not 
completely miscible, note their specific gravities in comparison 
with water and record this data in your notes (sp. gr. > 1 or < 1). 

Solubility tests in ether are carried out in a manner analogous 
to that described for the water solubility tests. Compounds 
falling in the borderline between what has been arbitrarily desig- 
nated " soluble " and " insoluble " should be sought in more than 
one group of the solubility table ; often the substance will be found 
classified in both places. The ether solubiHty test may often be 
applied in conjunction with the tests in water, dilute acid, or 

1 It is advisable to weigh this material to within 1 centigram. If this 
is not done, the beginner is liable to use as little as 0.02 g. of a light fluffy 
substance and on the other hand in dealing with heavy crystals a correspond- 
ingly large error is hable in the opposite direction. Small trip balances 
accurate to .01 g. should be available for this purpose. 



128 QUALITATIVE ORGANIC ANALYSIS 

alkali, provided that suitable recognition be given to the possible 
reactions of the unknown with either acid or alkali. 

Solubility in Dilute HCl. — In this test, it is advisable to utilize 
the same portion of unknown used in the water test. The proper 
amount of substance thus will be available, either dissolved or 
suspended in 3 cc. of water. To this solution or suspension add 
gradually with shaking ^ to 1 cc. of 20 per cent HCl. The final 
solution thus will contain about 5 per cent of HCl. The acid is 
added gradually (| cc. at one time) for the reason that certain 
organic bases form hydrochlorides that are only sparingly soluble 
in the excess of HCl. Such compounds may prove to be soluble 
after j cc. of acid has been added but may be insoluble in the 
excess. 

Question. — An unknown is soluble in water but a precipitate is formed 
when HCl is added. What can be predicted concerning the unknown? 

Solubility in Dilute KOH.^ — The material used in the water 
and in the acid solubility test may often be recovered and utilized 
for solubility in dilute KOH. When dealing with substances 
sparingly soluble in water (1 : 200 or less), it is convenient to use 
directly the solution or suspension from the preceding test. The 
acid solution is exactly neutralized by the addition of ^ to 1 cc. of 
30 per cent KOH, cooled to room temperature, and a further quan- 
tity (^ to 1 cc.) of KOH added gradually wdth cooling. 

Nitrogenous compounds that are found to be soluble in water 
but insoluble in ether should be tested for the evolution of ammo- 
nia or volatile amines when treated with alkali. This test is 
applied by placing a small amount of material on a watch-glass, 
moistening with strong KOH and noting the odor. The beginner, 
however, should not rely upon his olfactory sense for differentia- 
tion between ammonia and the volatile organic amines. 

Question. — An unknown is soluble in water but a precipitate is formed 
when KOH is added to the aqueous solution. What can be predicted con- 
cerning the unknown? 

Solubility in Cold Concentrated H2SO4. — The sulfuric acid 
test is of value in differentiating between Groups V and VI. 
Compounds falling in Groups I, II, III, and IV, as well as indif- 

' Potassium hydroxide is used here in preference to sodium hydroxide 
because the sodium salts of certain organic acids and phenols are sparingly 
soluble, particularly in excess alkali. Hydrochloric acid has been used in 
preference to sulfuric for the reason that the hydrochlorides of organic bases 
are often more soluble than the sulfates. 



THE SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 129 

ferent compounds containing N, S, etc., need not be subjected 
to the test in so far as classification is concerned. Since 
the test may give information of value apart from classification 
data (evolution of gases, charring, production of color, etc.), it is 
advisable to apply the test to each unknown examined. The 
student must refrain from placing any special reliance upon the 
numerous sulfuric acid color tests reported in the literature, since 
these are often greatly modified by traces of impurities. The 
test must be applied to the dry substance and cold concentrated 
acid must be used. Liquid compounds in Group V will usually 
dissolve quickly but solid compounds must be finely powdered 
and may require several minutes for solution. The applications 
and limitations of the test have been discussed in Chapter II. 

The following compounds are suggested for solubility work. 
All materials must be used sparingly. 



Class 

Hydrocarbons and 
Halogen deriva- < 
tives 



Ethers 

Esters 
Anhydride 

Acids 



Saturated aliphatic 

Aromatic 

Unsaturated 

AHphatic 
Aromatic 

Aliphatic (low mol. wt.) 
Aromatic 

Aliphatic (low mol. wt.) 
Monobasic 

Aromatic ■! Dibasic 

Amphoteric 



Ketones and AI- f Aliphatic 
dehydes I Aromatic 

Alcohols 



Phenols 

Nitro compounds 

Nitrile 



Individual selected 
Ligroin 

Ethyl bromide 
Toluene 
Bromobenzene 
Amylene 

Ethyl ether 
Anisole 

Ethyl acetate 
Ethyl benzoate 
Acetic anhydride 

Acetic acid 
Benzoic acid 
Phthalic acid 
AnthraniUc acid 

Acetone 
Acetophenone 

Amyl alcohol 
Ethyl alcohol 
Benzyl alcohol 

Phenol 
/3-Naphthol 

Nitrobenzene 
Trinitrotoluene 
Benzyl cyanide 



130 



QUALITATIVE ORGANIC ANALYSIS 



Amines, Amides, 
Imides, and 
RingN 



Sulfonic acids, 
Salts, and Car- 
bohydrates 



Primary amines 

Tertiary amine 

Negatively substituted (amide) 

Negatively substituted (imide) 

Ring nitrogen 



Aniline 
Benzidine 
Dimethyl aniline 
Acetanilide 
Phthalimide 
Quinoline 
Uric acid 

Ammonium benzoate 
Sodium benzoate 
Sodium benzene sul- 
fonate 
p-Toluidine hydro- 
chloride 
I Sucrose 



Supplement the above list with other typical compounds in 
which you are interested and in each case compare your results 
with the proposed solubility table at the end of this text. With 
the aid of your instructor apply any additions and corrections to 
this table. Do not proceed with laboratory work on identifica- 
tion of unknowns until you feel confident in being able to predict 
the solubilities of common organic compounds from the corre- 
sponding formulas without resorting to actual laboratory test; 
in other words, do not attempt to memorize any part of the Solu- 
bility Table, but instead, know the generalizations upon which the 
table is based. 

Record solubility data in the following manner : 





Solubility in 


Solu- 
bility 
Group 


Substance 


Water 


Dilute 
HCl 


Dilute 
KOH 


Cone. 
H2SO4 


Ether 


Piperidine 
hydrochlor- 
ide 

Phenyl sali- 
cylate 

Iso-amy 1 
ether 

m-Xylene — 


+ 

(sp.g.<l) 
(sp.g.<l) 


+ 


+ 
(ammonia- 
like odor) 

+ 


Evolution 
of HX 

+ 
+ 


+ 
+ 

+ 


II 

IV 

V 

VI 



THE SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 131 



Class-room Exercise. — Predict the solubility behavior of the 
following compounds and be prepared to give in each case the 
generalizations that lie at the basis of your answers. 

CH2OH • (CH0H)3 • CO2H CH3 • CH2 • CO • CH3 

CHs CH3 • (CH2)2 • CHCl • CO2 • (CH2)3 • OH 

CH3\ I /H 



CH3A ^Cl 



.n/ 



CH3 
^CH3 



A 


Br 








Y 

CH 


[3 






\A\NH2HBr 

'^.— SOsNa 


.CO2H 
A H 




CH3- 


i 

y 






Ot 

1 


[ 

— CH3 




,0H 

CioH6<^ 

\CO2Na 






V 

NO2 






C6H5CH2NHSO2C6H5 






CeHs • C2H5 




.CONH2 




^^^OCHs 


H 

CsHii'C-CHs 

1 












N 


\/ 


V( 


Z=^ 


CHs^^ 


K/ 


\ 


CO2 


•CHs 


h 



CHAPTER IX 

LABORATORY WORK ON CLASSIFICATION REACTIONS 
OF ORGANIC COMPOUNDS 

In the following experiments, note carefully and record imme- 
diately in your laboratory note-book all observations. Attention 
should be directed especially to the following phenomena: Heat 
effects, evolution of gases, changes in physical state (as for exam- 
ple the conversion of a liquid to a solid), changes in solubility, 
odors, color changes, etc. 

All observations should be recorded in a permanent laboratory 
note-book in the following manner: 

(a) Observations, 

(6) Reactions, written structurally, 

(c) Conclusions. 

Most of the experiments will consist of review work and 
the reactions may be interpreted with the aid of the knowledge 
gained in an elementary course in organic chemistry. The dis- 
cussion in Chapters II, III, IV, and V will prove of value but the 
student is expected to use also more advanced reference books. 
Special emphasis will be placed upon the interpretation of the 
reactions and the drawing of proper conclusions therefrom for the 
purposes of organic analysis. In doing this for any one experi- 
ment, it will often be necessary to utilize the results of other 
experiments. The limitations of the tests and the exceptions 
must be considered also in summarizing the results. No equa- 
tions are required for experiment 1. 

EXPERIMENT 1 

Ignite on a strip of platinum foil over a small flame a small 
amount (0.1 g.) of each of the following substances: (a) ligroin, 
(6) toluene, (c) benzoic acid, (d) ethyl ether, (e) glycerol, 
(J) ethyl alcohol, (g) trinitrotoluene, (h) amyl alcohol, (i) sodium 

132 



LABORATORY WORK ON CLASS REACTIONS 133 

acetate, (j) barium benzoate, (k) ammonium benzoate, (I) starch, 
and (m) urea. 

Ignition is the first test applied to any unknown compound. If the com- 
pound does not burn, what test should be applied? Note that certain organic 
compounds burn with the production of a large quantity of soot, while others 
burn merely with a luminous and sometimes with a non-luminous flame. 
Can any generalization be drawn in regard to this behavior? Review the 
results of the "burning tests" applied to methane, ethylene, and acetylene 
in your elementary course. Note that the luminosity of the flame is some- 
what dependent upon the quantity of material ignited. 

Is a residue left on ignition? If so, is it fusible or non-fusible? Is it an 
alkaline residue? Is it a carbonate? What is its color? Certain fusible 
residues may form a thin glassy coating on the platinum and thus escape 
detection by the beginner. Certain substances like starch may contain 
sufficient impurity to leave a trace of residue. Usually such a residue is 
easily differentiated from the amount left from the ignition of a typical salt. 

If the compound is a solid, does it possess a melting-point? If so, predict 
its melting-point to within about 25°. Most salts, and substances which 
decompose or sublime without melting need not be subjected to actual 
melting-point determinations . 

The odor of compounds upon ignition is often suggestive to the experi- 
enced analyst but care must be observed by the beginner because of the pos- 
sibiUty of meeting toxic products. 



TESTS FOR UNSATURATION 

EXPERIMENT 2 

Dissolve 0.2 cc. of amylene in 2 cc. of carbon tetrachloride and 
add gradually a 5 per cent solution of bromine in carbon tetra- 
chloride until a bromine color remains for about one minute. 

Repeat this experiment using in place of amylene equal weights 
of (a) phenol, (b) toluene, (c) allyl alcohol, (d) ethyl alcohol, (/) 
maleic or cinnamic acids, (g) acetophenone. Because of the limited 
solubility of cinnamic acid in carbon tetrachloride, 2 cc. of chloro- 
form should be used as a solvent. 

Why is carbon tetrachloride used as a solvent? How may one differ- 
entiate between addition of bromine and substitution by bromine? Suggest 
an experiment for determining whether addition is taking place as well as 
substitution. Would aniline respond to this test? What classes of com- 
pounds are readily substituted by halogens? Certain ethylene derivatives 
add bromine very slowly.. May such exceptions be predicted? 



134 QUALITATIVE ORGANIC ANALYSIS 



EXPERIMENT 3 

To 3 cc. of sodium carbonate (5 per cent) solution, add 0.2 g. 
of amylene and then drop by drop with shaking a 2 per cent solu- 
tion of potassium permanganate. Continue the addition until the 
permanganate color is no longer destroyed. 

Repeat this experiment using in place of amylene equal weights 
of (a) toluene, (6) cinnamic or maleic acid, (c) benzoic acid, and 
(d) salicylic acid or phenol. 

In this experiment, it is necessary to differentiate between a slight reaction 
due to impurities and a typical oxidation. For example, the impurities in 
technical toluene may react with a few drops of the permanganate solution 
but a reaction such as the oxidation of the side-chain to carboxyl would 
require 30 cc. of reagent. 

Does the permanganate test serve to detect those double unions that 
react only slowly toward addition of bromine? Does the bromine test (Exp. 
2) serve to modify conclusions drawn from Experiment 3? 

Test also benzaldehyde, acetone, glycerol, and ethyl alcohol. 

Under what conditions may copper acetylide be prepared? Is the for- 
mation of explosive metallic derivatives typical of all tri-bonded compounds? 

SATURATED HYDROCARBONS 

EXPERIMENT 4 

To ^ cc. of cyclohexane add 1| cc. of 20 per cent fuming 
H2SO4. Mix by shaking at first gently and then more vigorously. 
Allow the mixture to stand for several minutes to determine 
whether solution has taken place. Repeat the experiment using 
in place of cyclohexane (a) toluene or benzene, and (6) purified 
ligroin. 

The sign of reaction is the generation of heat and complete solution of 
the compound without excessive charring. Occasionally it is desired to sepa- 
rate the sulfonation product. This may be done by pouring the reaction 
mixture into 10 cc. of water, filtering (from what?), and saturating the filtrate 
with NaCl. Why is the above test not applied when the unknown dissolves 
in cold cone. H2SO4 or when it imdergoes decomposition with cone. H2SO4? 

Will the above differentiation apply also to the halogen derivatives of the 
hydrocarbons? If in doubt, apply the test to ethylene bromide and bromo- 
benzene respectively. 

How may nitration be used to differentiate between aliphatic and aro- 
matic hydrocarbons? How may the Friedel and Crafts Reaction be employed 
for this purpose? 



LABORATORY WORK ON CLASS REACTIONS 135 



EXPERIMENT 5 

To ^ cc. of benzene add 1 cc. of dimethyl sulfate. (Precau- 
tion !) Repeat this experiment using in place of benzene an equal 
volume of ligroin, petroleum ether, or kerosene. 

The reagent must not contain free sulfuric acid. Because of the reported 
toxicity of dimethyl sulfate, great care must be taken in handling it. The 
products from the above experiments are poured into 1 : 1 ammonia water 
to decompose the sulfate. If a drop of the ester touches the skin, the latter 
should be washed with water and then with ammonia solution. The toxicity 
of dimethyl sulfate may possibly be due to a methylation of haemoglobin. 

HALOGEN COMPOUNDS 

EXPERIMENT 6 

To 3 cc. of alcoholic silver nitrate solution, add one drop of 
benzyl chloride. After one minute heat the solution to the boiling- 
point and observe. 

Repeat the experiment, using in place of benzyl chloride one 
drop of each of the following compounds: (a) benzoyl chloride,^ 
(6) bromobenzene, (c) ethyl bromide, and (d) chloroform or car- 
bontetrachloride. 

In actual identification work when elementary analysis has shown the 
presence of halogen, this test should be preceded by the usual aqueous silver 
nitrate test for ionic halogen. Occasionally also free halogen acid may be 
present as an impurity. 

Halogen compounds show a similar distinction when boiled with alcoholic 
NaOH or KOH. How should this test be applied and why is alcoholic alkali 
used in place of the aqueous solution? 

EXPERIMENT 7 

To ^ cc. of water, add cautiously a few drops of acetyl chloride. 

Repeat the experiment, using in place of acetyl chloride two 
drops of benzoyl chloride.^ 

Repeat both parts of the experiment, using | cc. of aniline in 
place of water. 

Would halogen compounds like ethyl bromide and benzyl chloride react in 
a similar manner with aniline? What may be said about the relative reac- 

' The vapors of benzoyl chloride are very irritating to the eyes. Destroy 
all benzoyl chloride residues with cone. NH3 before pouring them into the sink. 



136 QUALITATIVE ORGANIC ANALYSIS 

tion velocities of alkyl halides in comparison with the reactivity of the acyl 
haUdes? How will substitution by halogen affect the physical and chemical 
properties of the various classes of compounds listed in the solubility table? 

ALCOHOLS, PHENOLS, ACIDS, ETC. 

EXPERIMENT 8 

Add small slices of metallic sodium to 1 cc. of pure amy] 
alcohol until no more dissolves. Cool the solution. Repeat the 
experiment, using toluene, acetone, amyl ether, etc. How can 
the test be applied to a solid substance? 

Why does ordinary ethyl ether react readily with metallic sodium? Some 
esters, ketones, amides, etc., also react. Write the equation for the reaction 
between sodium and acetoacetic ester. Some high-molecular-weight com- 
pounds that are also very feebly acidic may not dissolve in dilute aqueous 
alkali. Such compoimds are often detected by dissolving in alcohol and 
adding a little alcoholic sodium ethylate. (See Problem 3.) Tlie sodium 
test is never applied to compounds in Group IV; its main use is in differenti- 
ating between alcohols and ethers and, because of the interference by moisture, 
it is of limited value. 

Would halogen compounds ever interfere with the sodium test? , 

EXPERIMENT 9 

Add three | cc. portions of acetyl chloride to (a) 1 cc. of ethyl 
alcohol and (6) to 1 g. of phenol. After one minute pour the mix- 
tures separately into 5 cc. of water (Caution!). With the suc- 
tion pipette, separate the reaction product from (b) and test its 
solubility in dilute NaOH to determine whether the product is 
still acidic. 

Into a 2-oz. g.s. flask, place 2 cc. of ethyl alcohol dissolved in 
10 cc. of water. Add 2 cc. of benzoyl chloride and 10 cc. of 
20 per cent NaOH solution. Shake the mixture steadily for five 
minutes. 

What would happen if alcohol were omitted in the last experiment? What 
would be the result if ammonia were present in place of alcohol? Would 
phenols behave in a manner analogous to the alcohols? 

Compare the results of this experiment with those obtained in Experi- 
ment 7. 

EXPERIMENT 10 

Dissolve 3 drops of acetone in 2 cc. of water. Add j cc. of 
NaOH, and then drop by drop a solution of iodine in potassium 



LABORATORY WORK ON CLASS REACTIONS 137 

iodide until a pale yellow color remains. When a substance does 
not respond to this test at room temperature, warm the solution 
to 60° and, if the iodine color disappears, add a few more drops of 
iodine solution. 

Repeat this experiment, using in place of acetone (a) ethyl 
alcohol, (6) methyl alcohol (free from acetone), and (c) ethyl 
acetate. 

EXPERIMENT 11 

Add a drop of ferric chloride to very dilute (about xV per cent), 
aqueous solutions of (a) phenol, (6) resorcinol, (c) acetoacetic 
ester, and (d) benzoic acid. 

Some phenols which do not give a typical color with ferric chloride in 
aqueous solution will do so in alcohol solution. Apply the latter test when 
the results in water solution are negative. 

EXPERIMENT 12 

Add bromine water slowly to 5 cc. of dilute (about 1 per cent 
or less) aqueous phenol solution, until a faint bromine color 
remains. Repeat the experiment, using (a) aniline, (6) salicylic 
acid, (c) resorcinol, and (d) p-nitrophenol. 

This test has been used in connection with quantitative determinations 
of certain phenols. Do you expect phenol ethers and acyl derivatives of 
aromatic amines to act in the same manner? 

Explain why the substituted aniline precipitates instead of remaining in 
solution as the hydrobromide. Explain why a solution of sodium benzoate 
may give a precipitate with bromine water in spite of the fact that benzoic 
acid is only brominated at a fairly high temperature. What inorganic com- 
pounds might decolorize bromine with the formation of a precipitate? 

EXPERIMENT 13 

Heat in dry test-tubes at a temperature of about 140° (using oil 
or H2SO4 bath) for five minutes 0.2 g. of phthalic anhydride with 
about 0.1 g. of (a) phenol, (b) resorcinol, and (c) a-naphthol, the 
mixtures having been barely moistened with cone. H2SO4. 

Add the fusions separately to 10 cc. portions of cold water and 
neutralize the sulfuric acid with alkali. 

Write the formulas for phenolphthalein in acid and in alkaline solution. 
The production of fluorescein is often apphed also as a test for phthalic an- 



138 QUALITATIVE ORGANIC ANALYSIS 

hydride or phthalic acid. Succinic acid gives a similar color and this is true 
also of certain other dicarboxylic acids possessing the two carboxyl groups 
on adjacent C atoms. This test for phenols is not very general. 

EXPERIMENT 14 

Weigh on the accurate balance about two-tenths of a gram 

of some organic acid (benzoic may be used). Titrate the sample 

with standardized KOH solution (approx. N/10) using phenolph- 

"thalein as indicator. When dealing with difficultly-soluble acids, 

a few cubic centimeters of pure alcohol may be used as a solvent. 

Calculate the neutral equivalent of the acid according to the formula: 

Wt. of substance X 1000 



Neut. equiv. 



No. of cc. A^ alkali used' 



Why must phenolphthalein, in preference to methyl orange, be used as 
an indicator in the above experiment? 

The neutral equivalent of an acid is equivalent to the molecular weight 
divided by the number of acid groups titrated. What is the neutral equiv- 
alent of citric acid? When an acid is imperfectly dried, will the neutral 
equivalent be high or low? 

Determination of the neutral eqiuvalent may be applied to most car- 
boxylic acids. The presence of an aromatic amino group will not interfere 
appreciably in the titrations, but aliphatic amino groups or the presence of 
two aromatic amino groups will vitiate the results. 

Hydroxyl groups and even the presence of a single phenolic group, as in 
salicylic acid, will not interfere; e.g., ortho- and para-hydroxybenzoic 
acids possess neutral equivalents corresponding to the molecular weights. 
In general, the weakly acidic groups, like phenols, amides, and imides, give 
abnormally high neutral equivalents. What indicator should be selected for 
the titration of phenol? A strongly acidic phenol like s-tribromophenol 
may be titrated quantitatively in alcoholic solution using phenolphthalein. 

EXPERIMENT 15 

Weigh on the horn-pan balance 1.0 g. of benzoic acid and 1.5 g. 
of PCI5. Mix the materials in a dry test-tube and after sponta- 
neous reaction has taken place warm the mixture gently so as to 
dissolve the PCI5 completely. Pour the solution into 1 : 1 ammo- 
nia water and shake the mixture. 

This reaction is of considerable value for the preparation of derivatives 
of many acids. Why is the method not applicable to hydroxy acids and 
amino acids? 

In general, it is advisable to remove the phosphorus oxychloride before 



LABORATORY WORK ON CLASS REACTIONS 



139 



converting the acid chloride into the amide or anilide. This may be done 
by distillation, (b. pt. 107°) or by the method mentioned in Chapter X, 
pg. 150. 

Acids that are aliphatic in nature, e.g,. butyric acid, cinnamic acid, hydro- 
cinnamic acid, stearic acid, etc., may be converted into the corresponding 
acyl chlorides by means of PCI3. In these instances, the acid chloride is rela- 
tively insoluble in the by-product obtained and so may usually be separated 
mechanically. Write the equation for the reaction. 

The acid chlorides of hydroxy acids, Uke salicylic acid, may be prepared 
by means of thionyl chloride (SOCI2). 

PCI5 may act as a dehydrating agent upon certain organic compounds. 
It also rearranges oximes into amides (Beckmann rearrangement.) 

EXPERIMENT 16 



Prepare about 150 cc. of an approximately 1 per cent to 2 per 
cent acetic or propionic acid solution. Determine the total acidity 
by pipetting off 10 cc. of the acid solution and titrating against 
an approximately N/10 NaOH solution. Transfer 100 cc. of the 
acid solution to a 250 cc. distilling flask and distill two portions of 
10 cc. each, titrating them against the same NaOH solution. 
Express the results of each portion of the distillate in percentage of 
the total acidity of the 100 cc. used. 

The Duclaux values expressed in percentages are as follows: 





Formic 


Acetic 


Pro- 
pionic 


Butyric 


Valeric 


Iso- 
Butyric 


Iso- 
valeric 


Caproic 


1. 10 cc. 


3.95 


6.8 


11.9 


17.9 


24.5 


25.0 


28.7 


33 


2. 10 cc. 


4.40 


7.1 


11.7 


15.9 


20.6 


20.9 


23.1 


24 


3. 10 cc. 


4.55 


7.4 


11.3 


14.6 


17.0 


16.0 


16.8 


19 



Why is it unnecessary to use a standardized solution in the above titra- 
tion? 

An approximately N/10 solution is specified for the reason that the titra- 
tion with 1 or 2 per cent acid solutions will require a convenient volume of 
alkali for measurement in the burette. 

The Duclaux method was proposed for quantitative work but has been 
found of special value in connection with qualitative identification; e.g., we 
note the following ratios between formic, acetic, and propionic acids: 4:7: 12, 
ratios that are very much greater than those between the other physical 
constants. Moreover, these acids are usually met in aqueous solutions and 



140 QUALITATIVE ORGANIC ANALYSIS 

the isolation of the anhydrous acids when present in low concentrations is 
not a convenient operation. 

The method is of importance not merely in connection with the identi- 
fication of the eight compounds listed, but of any compounds that are readily 
converted into these acids, e.g., the esters, amides, nitrites, salts, etc. It is 
of course necessary that the total acidity of the solution be due entirely to 
the volatile acid present and not to inorganic acid. 

Outline the method for the identification of propionic acid in the solution 
obtained by the alkali hydrolysis of propionamide. 

ESTERS, ALDEHYDES, AND KETONES 
EXPERIMENT 17 

Determine the specific gravity at 20° of ethyl benzoate in one 
of the small specific gravity tubes (cap. about f cc). See page 
119, Fig. 10. 

Dissolve 2 g. of sodium in 50 cc. of absolute alcohol and add 
10 cc. of water after the sodium has dissolved. Withdraw a 10-cc. 
sample from the homogenous solution for titration against N/4 
acid for a determination of alkalinity. Place 40 cc. of the remain- 
ing alkaline solution into a 100 cc. r.b. flask and transfer quan- 
titatively from the specific gravity tube the weighed sample of 
ester. This may be done by means of the capillary tube used for 
filling the bulb. Small portions of the alcohol from the 40-cc. 
portion of sodium ethylate solution are used for the purpose of 
rinsing the tube. 

Boil the ester solution under the reflux for one-half hour, cool 
the contents of the flask, withdraw a 10 cc. portion of the alcoholic 
solution and titrate the excess alkali against the N/4 acid. From 
these values the saponification equivalent of the ester may be 
determined by the use of a formula identical with that used for 
calculating neutral equivalents of acids. 

.^ ,. . , . Wt. of ester X 1000 

feaponincation equivalent = ^r^^ ^-tt — ;-, — r-. 7. 

No. cc. 01 N alkah used 

The specific gravity tube is convenient for weighing samples intended 
for quantitative saponification, since a single trip to the balance serves not 
only for weighing the sample, but also for an accurate determination of the 
specific gravity — a constant which may prove of value in connection with the 
identification of the unknown. 

For esters of low molecular weight, the quantity of sodium used must 
be increased accordingly. 



LABORATORY WORK ON CLASS REACTIONS 141 

What values for saponification equivalent would be obtained from the 
following compounds: Ethyl succinate, ethyl acid phthalate, benzaldehyde, 
diamyl ether? 

EXPERIMENT 18 

Boil 2 cc. of ethyl benzoate in a small r.b. flask fitted with an 
efficient reflux condenser, with 30 cc. of 25 per cent NaOH. An 
ebullator tube will assist in preventing bumping. Saponification 
will be complete after about thirty minutes, as will be indicated 
b}'' the disappearance of the ester layer. 

A. Examination of the Neutral Saponification Product. — 
From the alkaline solution, distill about 4 cc. This fraction may 
be used for the identification of the alcohol in the case of an 
unknown. Water-soluble alcohols can be salted out with K2CO3, 

B. Examination of the Acidic Saponification Product. — Cool 
the residue in the distilling bulb and acidify with dilute H2SO4. 
Benzoic acid will separate. Do not mistake a precipitate of sodium 
sulfate for an organic acid. If in doubt, test the solubility of the 
product in ether. 

When an organic acid is soluble in water, other methods must be used to 
separate it, viz., (a) ether extraction, (6) distillation, (c) as an insoluble 
salt. When an ester yields an alcohol insoluble in water, the above indica- 
tion of completeness of saponification cannot be used. 

What kinds of esters yield alcohols that are non-volatile with water-vapor? 
How will a lactone behave when subjected to saponification? 

EXPERIMENT 19 

To 1 cc. of acetone add 1 cc. of saturated sodium acid sulfite 
solution and shake the mixture. 

To 10 cc. of a 40 per cent solution of sodium acid sulfite, add 
2\ cc. of ethyl alcohol. After several minutes, filter off or pour 
the clear solution from the small quantity of precipitated salt. 
This 20 per cent alcoholic solution of sodium acid sulfite is used 
in the following tests: 

To 1 cc. of the sulfite solution, add | cc. of acetone. Repeat 
the experiment, using in place of acetone a \ cc. portion of (a) 
benzaldehyde, (6) heptylaldehyde, and (c) acetophenone. 

The sulfite addition products of aldehydes and ketones of fairly low 
molecular weight are quite soluble in water. The progress of the reaction 
may be nevertheless followed by the generation of heat. Most ketones of 
high molecular weight do not react but the reaction is quite general for the 



142 QUALITATIVE ORGANIC ANALYSIS 

aldehydes. When deaHng with sparingly soluble aldehydes, particularly with 
solids, a 0.2 g. sample or such a quantity as will dissolve in ^ cc. of alcohol, 
may be added to 2 cc. of the sulfite solution. In this instance, the formation 
of the precipitate may simply be due to the throwing out of the organic 
compound because of dilution. If the initial compound is soluble in ether, 
it may easily be differentiated from a sulfite addition product, since the latter 
will be insoluble in ether. 

EXPERIMENT 20 

To 1 cc. of ammoniacal silver nitrate, add 1 drop of a 5 per cent 
sodium hydroxide solution. If a precipitate of silver oxide or 
hydroxide forms, add a drop of ammonia water so as to dissolve it. 

Add 2 drops of acetaldehyde solution. Observe whether or 
not reduction takes place. If the test-tube was previously 
cleaned with hot NaOH solution, silver is usually deposited in 
the form of a mirror. 

Repeat this test, using in place of acetaldehyde, not more 
than 2 drops of (a) acetone, (6) benzaldehyde. 

Many compounds, organic and inorganic, in addition to aldehydes, may 
reduce silver nitrate solution, e.g., the developers used in photography. (Write 
the formulas for the common compounds used for this purpose.) 

What explanation may be given for the failure of the aldehyde group in 
glucose to react with the reagent? When dealing with water-insoluble com- 
pounds ^ cc. of pure alcohol may be added. 

EXPERIMENT 21 

To 2 cc. of fuchsin-aldehyde reagent add 2 drops of acetalde- 
hyde solution. Repeat the experiment, using in place of acetal- 
dehyde 2 drops of (a) acetone, (h) benzaldehyde, (c) formaldehyde 
solution, and (d) acetophenone. 

In this experiment, the reagent should not be heated. Why? 

To differentiate between formaldehyde and acetaldehyde, add 1 cc. of 
25 per cent H2SO4 to each of the two test solutions. 

The reagent is prepared by dissolving 0.2 g. Fuchsin in 100 cc. of hot 
water, cooling, adding 2 g. of sodium bisulfite followed by 2 cc. of con. HCI, 
and diluting to 200 cc. 

Water insoluble compounds may be tested in the presence of alcohol 
(1 cc.) provided that the latter is of sufficient purity so as to give no appre- 
ciable color test. 

EXPERIMENT 22 
A. Water-soluble Aldehydes and Ketones. — Prepare some 
phenylhydrazine solution by dissolving 1 cc. of liquid phenyl- 
hydrazine in 3 cc. of 30 per cent acetic acid. Add ^ cc. of this 



LABORATORY WORK ON CLASS REACTIONS 143 

solution to a j-cc. portion of acetone dissolved in 3 cc. of water. 
Repeat the experiment using | ce. of a water-soluble aldehyde in 
place of acetone. 

B. Water- insoluble Aldehydes and Ketones are best tested 
in the following manner: 

Dissolve ^ g. (or less) of the material in a few cubic centimeters 
(usually 2 cc.) of ordinary alcohol. Now add water, drop by drop, 
until the precipitate barely redissolves. If by mistake a slight 
excess of water has been added, a few additional drops of alcohol 
must be used. To the clear solution, add a quantity of phenyl- 
hydrazine equal in weight to that of the unknown being tested. 
Observe. If the solution remains clear for several minutes, add 
1 drop of acetic acid and again observe. Test the following com- 
pounds; (a) benzaldehyde, (6) acetophenone or benzophenone. 

, Consider the relative advantages of hydrazones, semi-carbazones, and 
oximes. 

The hydrazones, when soUd, may be used as derivatives. The method 
of testing under B usually leads to a product of higher purity. The time 
required for the precipitation of the hydrazone is of value in predicting Some- 
thing concerning the nature of the compound. The reaction is not very 
accurate as a time test for the reason that supersaturated solutions may 
be formed. 

A trace of acetic acid catalyses the reaction. Many aldehydes give the 
test readily, whereas ketones usually require the addition of a drop of acid. 
This variation may possibly be due to the fact that most aldehydes contain a 
small quantity of acid as an impurity. The ketones differ among themselves 
in the time of precipitation. 

CARBOHYDRATES 
EXPERIMENT 23 

A. Fehling's Solution Test. — Dissolve 0.2 g. of glucose in 5 cc. 
of water. Add 5 cc. of Fehling's Solution and heat the mixture to 
the boiling-point. 

Repeat the experiment using in place of glucose 0.2 g. portions 
of (a) lactose, (6) sucrose, (c) maltose, and {d) glycerol. 

Dissolve 0.2 g. of sucrose in 5 cc. of water, add 2 drops of cone. 
HCl and heat the solution in the steam-bath for five minutes. 
Neutralize the free acid with alkali and apply the Fehling's Solu- 
tion test. Sucrose hydrolyzes far more readily than do most 
polysaccharoses. 



144 QUALITATIVTC ORGANIC ANALYSIS 

B. Osazone Formation. — Into a test-tube place 0.2 g. of a 
given carbohydrate, 0.4 g. of phenylhydrazine hydrochloride, 0.6 
g. of crystallized sodium acetate, and 4 cc. of distilled water. 
Plug the test-tube with cotton and set it into a beaker of boiling 
water. Note the time of immersion and the time of precipitation 
of the osazone. To prevent supersaturation, the tube must be 
shaken occasionally. Perform this experiment simultaneously 
with the following carbohydrates: Glucose, sucrose, maltose, and 
galactose. For time of osazone formation see page 155. 

AMINES 
EXPERIMENT 24 

To a few drops of aniline, add a few drops of acetyl chloride. 
Pour the reaction mixture into a cubic centimeter of water and 
note the separation of the acetyl derivative of aniline. Repeat 
the experiment with a few drops of dimethylaniline, in place of 
aniline. 

EXPERIMENT 25 

To I cc. of aniline, add 5 cc. of 10 per cent alkali solution 
and I cc. of benzenesulfonyl chloride. Warm the solution slightly. 
After all the acyl chloride has reacted, cool the solution, filter off 
any solid material, and acidify the clear filtrate. Agitate the 
mixture to cause solidification. 

HoAy may the benzenesulfonjd chloride test be used to dif- 
"Terentiate between primary, secondary, and tertiary amines? 
(Page 183.) 

EXPERIMENT 26 

The general method of diazotizating a primary aromatic 
amine is as follows : Dissolve 1 mole of amine in 2| moles of hydro- 
chloric acid. Cool to 0°. Add with stirring a cone, solution con- 
taining 1.05 moles of NaNOo. 

A. Dissolve 1 cc. of aniline in 3 cc. of cone. HCl and add 
5 cc. of water. Cool the solution to 0°. Add 0.8 g. of NaN02 
dissolved in 3 cc. of water. Apply the following tests to this 
solution. 

(a) Warm 5 cc. of the solution and note the liberation of gas. 
The latter may be collected over cone. KMn04 solution to differ- 



LABORATORY WORK ON CLASS REACTIONS 145 

entiate it from oxides of nitrogen. Does the aqueous solution 
give a phenol odor? 

(6) Dissolve 0.1 g. of /3-naphthol in 1 cc. of 5 per cent NaOH, 
and 4 cc. of water. Cool the solution to 10° and add 1^ cc. of the 
cold diazonium solution. 

B. Repeat the first part of the above experiment, using 1 g. of 
N-monomethyl aniline in place of aniline. Note the separation of 
the neutral nitroso compound (see page 64). 

How may the diazotization of amines be used in qualitative organic 
analysis to differentiate between various types of amines? 

INDIFFERENT GROUPS (CONTAINING NITROGEN) 
EXPERIMENT 27 

A. Place a few crystals of ammonium benzoate on a watch- 
glass and add a cubic centimeter of dilute alkali. Note the strong 
odor of ammonia. Repeat the experiment with (a) urea, (6) 
benzamide, (c) benzonitrile. 

B. Place I g. of urea into a test-tube, add 2 cc. of 20 per cent 
NaOH solution and boil the solution gently. Is ammonia evolved? 
Repeat the experiment using in place of urea (a) benzamide, (6) 
acetanilide. 

What variation is noted in the ease of hydrolysis of various amides? A 
part of this variation is due to differences in solubility of the organic com- 
pound in the aqueous solvent used. The addition of 1 cc. of alcohol will 
hasten the hydrolysis of water-insoluble compounds. 

EXPERIMENT 28 

A. To I g. of p-nitrochlorobenzene, add about 1 g. of granulated 
tin and add in small portions a few cubic centimeters of 1-1 HCl. 
Finally, heat the mixture gently. The nitro compound should 
disappear completely. Pour the reaction mixture into about 10 
cc. of water and add enough concentrated NaOH solution to 
dissolve most of the precipitate of tin hydroxide at first formed and 
distil a portion of the solution. 

The product may be shown to be an amine by its solubility in dilute acid, 
whereas the original nitro compound was insoluble in dilute acid. Which 
amines will be non-volatile with water vapor? How may they be separated 
from the tin-salt solution? 



146 QUALITATIVE ORGANIC ANALYSIS 

B. Into a small beaker, place 10 g. of iron powder and 5 cc. 
of water. Add 1 cc. of 5 per cent HCl, and then 1 g. of p-nitro- 
toluene. Stir the mixture with an iron spatula, warming gently to 
start the reduction. The mixture should be in the form of a paste, 
but to prevent solidification, ^-cc. portions of water may be 
added. Finally heat in a water-bath for ten minutes with stirring. 
The p-toluidine may be separated by adding 25 cc. of water and 
distilling, or it may be separated by extracting the iron paste with 
10 cc. of benzene. Note that the product is completely soluble 
in dilute HCl, thus showing the absence of unchanged nitro com- 
pound. 

In the above reduction, difficultly-soluble nitro-compounds may react 
slowly. In such instances, 2 cc. of alcohol may be added with the nitro com- 
pound. 

When p-nitrobenzoic acid is reduced by method B, how may the p-amino 
acid be separated? What precautions must be taken because of the ampho- 
teric nature of the amino acid? 

EXPERIMENT 29 

Place 1 g. of p-bromoacetanilide into a small round-bottom 
flask and add 15 cc. of a mixture of equal volumes of sulfuric acid 
and water. Boil under the reflux for one-half hour or until a por- 
tion of the liquid on dilution does not give a precipitate of the 
original substance. Dilute the hydrolysis mixture with about 50 
cc. of water and precipitate the p-bromoaniline by the addition of 
alkali. 

Other reagents for hydrolysis are alcoholic alkali, alcoholic 
hydrochloric acid, and strong acids under pressure. 

Repeat the above experiment with (a) acetanilide, and (6) 
benzamide, in place of p-bromoacetanihde. 

Why does aniline fail to precipitate under the above conditions? How 
may it be isolated as free aniline? As benzanilide? When benzamide is 
used, why must the above criterion of completeness of saponification be 
modified? 

EXPERIMENT 30 

Dissolve 1 drop of nitrobenzene in 1 cc. of 75 per cent alcohol. 
Add a drop of NaOH solution and observe any color change. Add a 
small fragment of 3 per cent sodium amalgam and note any color 



LABORATORY WORK ON CLASS REACTIONS 147 

changes. Does the amalgam liquefy more readily than in a blank 
portion containing no nitro compound? 

Apply this test to p-nitrobenzoic acid and to other nitro com- 
pounds. If the unknown gives a very deep color with alkali 
alone, the amalgam test should not be applied. 

Certain nitro compounds in place of reduction to the azo stage under 
the conditions of the above experiment, form only the Ught-colored azoxy 
compounds. In some instances the azoxy derivative will be only sparingly 
soluble in 75 per cent alcohol, and if so may be used as a derivative. Com- 
pounds that dissolve in dilute alkah and which possess groups such as nitro, 
nitroso, azo, etc., are very readily reduced to the corresponding amino com- 
pounds by means of sodium hydrosulfite (Na2S204) in aqueous solution. 



CHAPTER X 

THE PREPARATION OF DERIVATIVES 

Color reactions, the precipitation of an insoluble compound at 
a given stage in the analysis, decomposition with certain reagents 
— reactions that are often used with safety in inorganic anal3'sis 
as final tests of identification, are applied in organic analysis only as 
indications. Fortunately, in organic analysis, we may rely more 
often for final identification upon a variety of physical constants, 
not only of the unknown, but also of its derivatives. Very often 
the elementary analysis of an unknown, together with a knowledge 
of its solubility behavior and its class reactions, will have demon- 
strated so clearly the type of compound dealt with that the physi- 
cal constants of the unknown point to but one conclusion. Such 
a circumstance, however, will seldom justify the failure to prepare a 
suitable derivative and the identification of the latter by means of 
its main constants. In this manner, the final possibility of error 
may be obviated. For special cases, a series of derivatives may be 
prepared and identified. 

THE CHARACTERISTICS OF GOOD DERIVATIVES 

1. The compound selected for a derivative should possess 
physical and chemical properties which will enable an absolute 
differentiation to be made between the individual possibilities. 

2. Solid derivatives are preferable, because of the ease of ma- 
nipulation of small quantities in preparation and purification, as 
well as in the determination of constants. 

3. The derivative should be prepared by a reaction which gives 
a good yield of fairly pure product. 

4. The derivative should be prepared preferably by a general 
reaction which under the same conditions would yield a definite 
derivative with the other individual possibilities. This will elim- 
inate the necessity for a series of specific reactions. 

148 



THE PREPARATION OF DERIVATIVES 149 

In connection with the apphcation of class reactions, sohd 
derivatives are often obtained which may serve for use in the final 
identification work. When this is the case, the time required to 
complete an analysis will be materially lessened. 

Occasionally a derivative is met which possesses a melting- 
point close to that of the unknown; when the product of a reaction 
melts close to or somewhat lower than the melting-point of the 
original unknown, the student should question whether or not the 
original unknown has been recovered, and he should apply addi- 
tional tests as shown in the following examples: 

A. Suppose it is necessary to differentiate between ortho and 
meta nitrobenzoic acids. Is the amide a suitable derivative? 

/M-nitrobenzoic acid m.p. 142° Amide m.p. 142° 
o-nitrobenzoic acid m.p. 146° Amide m.p. 176° 

In this instance, the amide may serve as a perfectly satisfactory 
derivative, even though the unknown happens to be the meta 
compound and the reaction product from amidation melts, let 
us say, at 140-141°. It will be necessary, however, to demon- 
strate that amide formation has actually taken place and that the 
reaction product is no longer soluble in dilute alkali. In addition, 
mixed melting-points of the original acid with some of the known 
acid and of the derivative with known ?n-nitrobenzamide will 
remove all doubt. 

B. What derivative, satisfying all (and in particular the 
fourth) characteristics of a good derivative, can be recommended 
to differentiate between the four mono-chloro derivatives of tol- 
uene? 

o-Chlorotoluene b.pt. 159° 

m-Chlorotoluene b.pt. 162° 

p-Chlorotoluene b.pt. 162° 

Benzyl chloride b.pt. 179° 

The greater reactivity of the halogen in benzyl chloride will serve, 
of course, to indicate side-chain halogen. By oxidation with alka- 
line permanganate, all four individuals yield derivatives, and no 
special modification of the oxidation method is required for the 
individual compounds being oxidized. The melting-points of the 
corresponding acids are 148°, 155°, 240°, and 122°, respectively. 
The melting-points of the ortho and meta chlorobenzoic acids 



150 QUALITATIVE ORGANIC ANALYSIS 

(148° and 155°) lie too close together for absolute differentiation. 
Accordingly, mixed melting-points are resorted to in order to 
avoid the possibility of error. 

THE CHOICE OF DERIVATIVES FOR SOME OF THE COMMONER 
CLASSES OF COMPOUNDS 

In the following discussion, the various types of derivatives 
that are commonly used are mentioned in approximately the order 
of their importance in the elementary work of this course. The 
experimental procedures involved can be outlined in only the most 
frequently occurring instances and the physical constants of only 
a limited number of common compounds can be referred to within 
the limits of the chapter. 

Derivatives for Alcohols 

1. Solid esters. 

(a) Dinitrobenzoates. 
(6) Benzoates. 
(c) Acetates. 

2. Urethanes. 

3. Acid phthalates. 

4. Oxidation products. 

5. Halogen derivatives. 

la. The 3, 5-dinitrobenzoates are convenient derivatives for 
the water-soluble mono-hydroxy alcohols. MuUiken, I, 168. 

In a small test-tube, mix 0.3 g. of 3, 5-dinitrobenzoic acid and 0.4 g. 
of PCU. Warm the mixture slightly to start the reaction and when the rapid 
reaction subsides, heat the mixture gently for about one minute, when the 
evolution of HCl should cease. Pour the mixture upon a watch-glass (hood) 
and after solidification, press the pasty solid upon a clay plate to remove the 
POCI3. Place the powder into a dry test-tube, add 0.6 cc. of the alcohol, 
stopper the tube loosely, and warm the reaction mixture on the water-bath 
during about 10 min. Now add 5 to 10 cc. of water and filter after the prod- 
uct has solidified. Transfer any solid material back to the test-tube and 
crystallize the ester from about 5 to 10 cc. of ethyl alcohol-water mixture 
of such strength that the ester will dissolve in the warm solution but will 
crystalUze out on cooUng. Dry the material on a porous plate and determine 
its melting-point. 

In actual practice, the above experiment should be carried out by using 
a known compound side by side with the unknown. The dinitro-benzoyl- 
chloride is prepared in exactly double quantity, which, after drying, is divided 
into two equal portions. Thus we may apply the method to a considerable 
number of alcohols, the dinitrobenzoates of which may not be recorded in 
the literature. Moreover, material is then at hand for the determination of 



THE PREPARATION OF DERIVATIVES 



151 



mixed melting-points. The latter precaution is especially important, since 
some of the above melting-points lie rather close to one another and the 
boiling-points of some of the original material, especially of the higher alcohols, 
may be lowered by the presence of moisture. 



Alcohol 


Boiling-point 
Alcohol 


Melting-point 

3, 5-Dinitroben- 

zoate 


Melting-point 
p-Nitrobenzoate 


Methyl 

Ethyl 

Propyl 

n-Butyl 

Isobutyl 

/3-Chlorethyl 

7-Chloropropyl 

Benzyl 


66° 
78° 
97° 
116° 
108° 
132° 
162° 
205° 


107° 
92° 

73° 
64° 
83° 
88° 
54° 
106° 


96° 
57° 



Allyl alcohol may be converted into a dinitrobenzoate m. 48°, 
but it should also be subjected to titration with bromine solution. 
Isopropyl alcohol may be readily oxidized to acetone by means 
of chromic acid and the ketone identified by the method given 
below for acetone. 

lb. Benzoates. — A few of the polyhydroxy alcohols (as for 
example ethylene glycol and glycerol) are readily converted into 
solid benzoates. In the reaction (Schotten-Baumann) an appre- 
ciable excess of benzoyl chloride is used together with sufficient 
NaOH (10 per cent) to neutralize the acid liberated as well as to 
decompose the excess acyl halide. The method may be applied 
also with other acyl halides (p-nitrobenzoylchloride, 3, 5-dinitro- 
benzoylchloride, etc.) which are but slowly decomposed by water. 



Alcohol 



Ethylene glycol . . . . 
Trimethylene glycol 
Glycerol 



Boiling-point of 
Alcohol 



197° 
216° 
290° d. 



Melting-point of 
Benzoate 



70° 
53° 

72° 



Ic. Acetates. — Certain high molecular weight alcohols, as 
well as certain polyhydroxy alcohols, yield solid acetyl derivatives. 
This tj^pe of derivative will be met again among the sugars. 



152 



QUALITATIVE ORGANIC ANALYSIS 



The polyhydroxy-alcohols with four and six hydroxyl groups 
react with benzaldehyde in hydrochloric acid solution to yield 
sparingly soluble benzal derivatives, but, unfortunately, such 
derivatives, as for example, those of erythrite, mannite, dulcite, 
and sorbite, all melt in the neighborhood of 200°-220°. 

2. Urethanes. — The phenyl urethanes are readily prepared by 
combining phenyl isocyanate with a slight excess ^ of alcohol, 
warming if the reaction is not spontaneous, and recrystallizing 
the resultant urethane from a suitable solvent. The diphenyl 
carbamates are prepared from diphenyl carbamyl chloride 
(CgH5)2N • CO • CI but usually a fairly high temperature is required 
to induce reaction. The phenyl urethanes of methyl, ethyl, 
propyl, and butyl alcohol all melt within the range of 47° to 61°. 



Alcohol 


Boiling-point of 
Alcohol 


Melting-point of 
Alcohol 


Melting-point of 
Phenyl Urethane 


Benzyl 

Phenyl Ethyl 

Cinnamyl 

Linalool 

a-Terpineol 

d-Borneol 


204° 
220° 
257° 
198° 
217° 
212° 


33° 

35° 
203-4° 


78° 

79-80° 

90° 

65° 

.113° 

138° 







3. Acid Phthalates. — The preparation of acid phthalates and 
their use for differentiation between primary, secondary, and ter- 
tiary alcohols has been discussed in Chapter III. n-Butyl and 
benzyl alcohols, citronellol, geraniol, etc., are conveniently iden- 
tified by this method. 

4. Oxidation Products. — Aromatic alcohols possessing the 
group -CH2OH may readily be oxidized to the corresponding acid. 
Example: Benzoic acid from benzyl alcohol. The method is 
similar to that to be outlined later in this chapter for the oxida- 
tion of side-chains of aromatic hydrocarbons except that the 
reaction is more rapid and the yields are higher. 

5. Halogen Derivatives. — The replacement of the alcoholic 
-OH group with either bromine or iodine is a typical reaction of 
alcohols. Since the resulting derivatives are usually liquids, this 

1 Reaction of phenyl isocyanate with water leads to the formation of the 
water-insoluble diphenylurea. 



THE PREPARATION OF DERIVATIVES 



153 



reaction is used only when considerable amounts of the unknown 
are available. 

Derivatives for Aldehydes and Ketones 

1. Aryl hydrazones. 

2. Semicarbazones. 

3. Oximes. 

4. Special condensation products. 

5. Oxidation products. 

1. Aryl Hydrazones. — The phenylhydrazones of aldehydes and 
ketones of low molecular weight are generally liquids not adapted 
for derivatives. By using p-bromo-phenylhydrazine, p-nitro- 
phenylhydrazine, or /3-naphthylhydrazine, solid derivatives often 
may be obtained. On the other hand, among the aromatic 
compounds even the lower members yield solid phenylhydrazones. 





Melting-point of 
Phenylhydrazone 


Furfural 

Benzaldehj'de 


97° 
156° 
103° 


Acetophenone 



The method of preparing phenylhydrazones is outlined in Chapter 
IX, Exp. 22. 

2 and 3. Semicarbazones and Oximes. — Semicarbazones and 
oximes of aldehydes and ketones are generally white crystalline 
solids, the former being usually the less soluble. Several of the low 
molecular weight carbonyl compounds, however, yield liquid 
oximes and it is best to use the semicarbazones for identification of 
water-soluble carbonyl compounds and the oximes for water- 
insoluble unknowns. 

Preparation of a Semicarbazone. — 0.5 cc. of the unknown and 0.5 g. of 
Semicarbazine HCl are dissolved in 5 cc. of water. About 0.7 g. of crystal- 
lized sodium acetate is added and the solution set aside for an hour or more 
in order to permit the semicarbazone to crystaUize. The derivative should 
be recrystallized from a small portion of water. 

Preparation of an Oxime. — Oximes of water-soluble carbonyl compounds 
may be prepared in a manner analogous with that described for the semi- 



154 QUALITATIVE ORGANIC ANALYSIS 

carbazones, using a hydroxylamine salt in place of the hydrazine derivative. 
Occasionally the oxime must be isolated by ether extraction. The following 
procedure is adapted for water-insoluble compounds: 

Dissolve 0.5 g. of hydroxylamine hydrochloride in 2-3 cc. of water, add 
2 cc. of 10 per cent NaOH solution, 0.2 g. of the unknown, and exactly suf- 
ficient alcohol to dissolve the organic compound. The oxime is generally 
sparingly soluble and may crystallize from the dilute alcohol as it is formed. 
Often it is best to warm the reaction-mixture on the steam-bath for 10 minutes, 
using a condenser to avoid loss of solvent. If no sign of reaction is noted after 
one hour, the mixture is diluted with 2 volumes of water and the precipitated 
product tested to determine whether it is the oxime or the original unknown. 
The oximes are usually soluble in dilute alkali and may be reprecipitated by 
exact neutralization of the alkahne solution. Why is an excess of acid to be 
avoided? 

4. Special Condensation Products. — Several of the most com- 
mon carbonyl compounds (formaldehyde, acetaldehyde, and 
acetone) are derivatized best by means of condensation reactions 
other than those discussed above; the two aldehydes may be con- 
densed with /3-naphthol according to the directions outlined by 
MulKken, I, pages 23-25. 

Methylene-di-jS-naphthol, m. 189-92° 
Ethylidene-di-/3-naphthyloxide, m. 172-3° 

The same derivatives can be applied to compounds like methylal 

and acetal, which may be hydrolyzed to yield the above aldehydes. 

Acetone may be condensed (Claisen Reaction) with benzalde- 

hyde under the influence of alkali to yield dibenzylidene acetone, 

/^ 
CeHsCH^CH— C — CH^CH— CeHs 

m.p. 111-112°. Three drops of the ketone are dissolved in 2 cc. 
of alcohol and 0.5 cc. benzaldehyde and 1 cc. dilute alkali added 
The mixture is heated to boiling for a minute, cooled, and then 
agitated in order to cause the supercooled oil to solidify. Crys- 
tallization from alcohol yields a pure material. 

5. Oxidation Products. — Aromatic aldehydes are very readily 
oxidized to the corresponding acids; some of the members (ben- 
zaldehyde, for instance) are readily oxidized even by atmos- 
pheric oxygen. A general procedure outlined below for the oxi- 
dation of the side-chains of aromatic hydrocarbons is generally 
applicable to aldehydes also, except that only one-third of the 



THE PREPARATION OF DERIVATIVES 155 

quantity of permanganate is used. Can this method be recom- 
mended for phenoHc aldehydes, such as saUcyl aldehyde, naph- 
thol-aldehydes, etc.? 

CARBOHYDRATES 

No great reliance can be placed upon the melting-points of 
sugars and their derivatives; the values vary with the rate of 
heating and in the case of the osazones there is too little variation 
between melting-points of the individual members. It is for- 
tunate, therefore, that an additional, accurately determinable 
constant is available, namely, the specific rotation. The value for 
this constant should always be determined in connection with the 
final identification of a soluble carbohydrate. 

Derivatives for Carbohydrates 

1. Osazones. 

2. Hydrazones. 

3. Acetyl derivatives. 

4. Mucic acid. 

5. Formation of furfural. 

1. Osazone formation has been amply illustrated in connec- 
tion with the classification reactions (see pages 144 and 84). 
Mulliken gives the following approximate figures for the " Time 
Test": 

Mannose h min. (ppt. is the hydrazone) 

d-Fructose 2 min. 

d-Glucose 4-5 min. 

Z-Xylose 7 min. 

Z-Arabinose 10 min. (oily) 

d-Galactose 15-19 min. 

Saccharose (cane sugar) 30 min. 

RafRnose 60 min. 

Lactose No ppt. from hot solution 

Maltose No ppt. from hot solution 

The crystalline form of the osazones should be compared under 
the microscope with that of derivatives prepared from known 
sugars. Which four of the above sugars yield identical osazones^ 
and why? 



15G 



QUALITATIVE ORGANIC ANALYSIS 



2. Hydrazones. — For identification by means of melting-points, 
the hydrazones are of more value than the osazones, but they 
possess the disadvantage that many of them are soluble in water 
and therefore isolated with difficulty. The phenylhydrazone of 
mannose is very sparingly soluble, the corresponding hydrazones 
of arabinose and galactose are soluble in 50-75 parts of water but 
not precipitated in such dilutions, whereas those of glucose and 
fructose are very soluble. A variety of other aryl hydrazones, such 
as p-bromophenylhydrazones, a-methylphenylhydrazones, etc., are 
also available for the identification of sugars. Cf. Rosenthaler, 
pages 176-234. 



Sugar 


Melting-point 
Phenylhydrazone 


Glucose 

Arabinose 

Galactose 

Mannose 

Fructose 


144-146° 
150-153° 
158-160° 
195-200° 
? 



3. Acetyl Derivatives. — The acetyl derivatives of sugars may be 
prepared by the use of acetic anhydride in the presence of a cata- 
lyst, such as anhydrous sodium acetate or zinc chloride. Isomeric 
acetyl derivatives may be obtained, the result depending upon the 
particular catalyst used. (J. Ind. Eng. Chem. 8, 380, 1916.) 

An Illustration of the Preparation of an Acetyl Derivative. — 1 g. of galactose 
is gently heated with 15 cc. of acetic anhydride in the presence of 1 g. of 
freshly fused sodium acetate. The solution is heated at the boiling-point 
for 10 minutes. The acetic anhydride is volatilized by warming on the water- 
bath (hood), a little alcohol being added to aid in the removal of the anhydride. 
The residue is washed with cold water to remove sodium acetate and the 
j3-pentacetyl galactose crystallized from alcohol. 



/3-pentacetyl galactose 
/3-pentacetyl glucose 



Sodium Acetate 
m. p. 142° 
m. p. 132° 



Zinc Chloride 
a-form 95° 
a-form 111-112' 



For further information, the publications of Hudson should be consulted: 
J. Am. Chem. Soc. 37, 1267-1285, 1589-93 (1915). 

4. Mucic Acid, — Galactose and its derivatives (lactose, galac- 
tosides, etc.), yield the insoluble mucic acid upon oxidation with 



THE PREPARATION OF DERIVATIVES 157 

nitric acid. A portion of the sugar is slowly evaporated on the 
water-bath with ten times its weight of nitric acid (sp. gr. 1.15) 
until a thick syrup is obtained. This is diluted with a little water 
and allowed to crystallize during one hour. Oxalic acid may also 
crystallize out but this is readily soluble in warm alcohol. Mucic 
acid melts at 213°d. 

ACIDS 

In connection with the identification of organic acids, the neu- 
tral equivalents should always be determined. (See page 138.) 
The volatile aliphatic acids (formic to valeric) should be charac- 
terized by means of the Duclaux Constants. 

Derivatives for Acids 

1. Amides, anilides, and toluidides. 

2. Solid esters. 

3. Elimination of CO2. 

4. Anhydrides and miscellaneous derivatives. 

1. Amide formation has already been outlined in connection 
with the laboratory work, page 138. Low molecular weight acids 
yield water-soluble amides, and for this reason it is advisable to 
prepare instead the less soluble anilides or p-toluidides (page 144). 
MuUiken, I, 80-81, has outlined convenient directions for the iden- 
tification of acetic, propionic, butyric, and isobutyric acids in the 
form of the corresponding p-toluidides. These acids are usually 
met in aqueous solution and it is not feasible to convert them into 
acyl halides; instead, the aqueous solution is neutralized with 
NaOH, evaporated, and the resultant sodium salt utilized in the 
test. 

Preparation of p-Toluidides. — In a dry test-tube, mix 1 g. of p-toluidine, 
0.4 g. of the powdered sodium salt, and 0.4 cc. of concentrated HCl. Boil 
the mixture very gently over a very small gas flame during 15 to 30 minutes. 
Cool, extract the reaction product with 5 cc. of boiling 95 per cent alcohol, 
pour into 50 cc. of hot water contained in a beaker, and boil down to a volume 
of about 10 cc. Filter the hot solution through a small filter paper in a heated 
funnel, crystallize the toluidide from the filtrate, dry, and take its melting- 
point. Sometimes recrystallization is necessary. 

Melting-point 

Acet-p-toluidide 146-147° 

Propion-75-toluidide 123-124" 

Isobutyr-p-toluidide 104-105° 

n-Butyr-o-toluidide 72-73° 



158 QUALITATIVE ORGANIC ANALYSIS 

2. Solid Esters. — A limited number of common acids ^ form 
solid esters with methyl alcohol; in such instances, the usual 
esterification process, using 0.5 g. of acid, 3 cc. of methyl alcohol, 
and I cc. of concentrated H2SO4 may be applied. After reflux- 
ing for 15-30 min., the reaction mixture is poured into 10 cc. of 
water, the ester filtered off, and recrystallized. Ethyl esters gen- 
erally melt lower than the methyl derivatives and with increase in 
molecular weight of the alkyls lower melting-points are observed. 
(See table on page 151.) With alcohols of fairly high molecular 
weight, solid esters are again obtained. 

Reid has proposed the p-nitrobenzyl esters 

(R-C^O-CH2-C6H4-N02) 
and the phenacyl esters 

(R-C^O-CHs-C^CgHs) 

as convenient derivatives for the identification of hundreds of 
organic acids.- 

The p-nitrobenzyl esters are prepared by boiling an alcoholic 
solution of the sodium salt of the organic acid with p-nitrobenzyl 
bromide. For the preparation of phenacyl esters, w-bromoace- 
tophenone, is used in place of the nitro-benzyl bromide. In the 
more recent papers in the above series is discussed also the separa- 
tion and identification of mixtures. 

Method. — Dissolve 1 g. of the sodium or potassium salt of the organic 
acid (accurately neutralize free acids with alkaU and evaporate) in a boiling- 
mixture of 5 cc. water and 10 cc. 95 per cent alcohol. Add 1 g. of p-nitro- 
benzyl bromide and boil the solution during 30 minutes. If an insoluble 
ester separates from the hot solution, slightly more alcohol may be added. 
Finally, the solution is cooled, the crystalline ester filtered off, recrystallized 
from dilute alcohol, and the melting-point taken. Valuable details will be 
found in the original articles. 

3. Elimination of CO2. — Malonic acid and its homologues read- 
ily lose CO2 when heated to a temperature of about 140-160°. 
This reaction also takes place at a lower temperature when a solu- 
tion of the dicarboxylic acid in 20 per cent H2SO4 is refluxed. The 

1 m- and p-Nitrobenzoic acids, the dinitrobenzoic, certain halogenated 
benzoic acids, terephthahc acid, etc. 

-J. Am. Chem. Soc. 39, 124, 304, 701, 1727 (1917); 41, 75 (1919); 42, 
1043 (1920); 43, 629 (1921). 



THE PREPARATION OF DERIVATIVES 159 

resultant monocarboxylic acid may be identified by the methods 
given above. 

Monocarboxylic acids, particularly in the aromatic series, lose 
CO2 when heated with soda-lime; in dealing with carboxy deriva- 
tives of solid hydrocarbons, this method may prove applicable. 
For example, the naphthoic acids {a and /3) will yield the easily- 
sublimable naphthalene. In general, synthetical reactions prove 
superior to analytical reactions for the preparation of deriva- 
tives. Why? 

4. Miscellaneous. — A variety of common acids may be con- 
verted into characteristic derivatives by methods not covered 
by the above. Details for these less general cases cannot be given 
here, but a few examples will be cited. 

o-Phthalic acid, when heated to its melting-point and main- 
tained at that temperature for a short time, yields the very char- 
acteristic, readily-sublimable phthalic anhydride, m.p. 132°. 

Cinnamic acid, in common with certain other side-chain unsat- 
urated acids, may be characterized as the dibromide addition 
product. 

Phenolic acids may be identified by reactions involving sub- 
stitution in the aromatic nucleus. For example, salicylic acid is 
usually converted into the 5-nitro derivative. Mulliken, I, 
p. 85. 

,CH2R 

Acids of the type, QQB.^<f , may be oxidized by the 

\CO2H 

methods used for side-chain oxidation of aromatic hydrocarbons. 

PHENOLS 

1. Diphenyl urethanes. 

2. Nitration or bromination products. 

3. Picrates. 

4. Acetyl or benzoyl derivatives.^ 

The acetyl and benzoyl derivatives of many common phenols 
are liquids or low-melting solids and hence they are suitable for 
characterization in only a limited number of cases. The diphenyl 
urethanes prepared with the aid of diphenyl carbamine chloride 
(see example below) are more generally applicable. Mulliken, 
I, pages 108-110, outlines directions for nitration of phenol, 

' For recent work on the dinitrobenzoates of phenols see J. Am. Phar. 
Assn. 11, 608 (1922). 



160 QUALITATIVE ORGANIC ANALYSIS 

phloroglucinol, resorcinol, and thymol; the bromination of phenol 
and pyrocatechin; and the conversion into picrates of a- and /3- 
naphthols. 

Preparation of Diphenyl Urethanes of Phenols. — Dissolve 1 g. of the phenol 
in 5 cc. of pyridine, add 1 g. of diphenyl carbamine chloride and reflux gently 
during 30 minutes. The reaction mixture is poured into water. The 
derivative is filtered off and crystallized from alcohol. 

Melting-points of Diphenyl LTrethanes 

Phenol 104-105° 

o-Cresol 72-73° 

??i-Cresol 100-101° 

p-Cresol 93-94° 

/i-Naphthol 140-141° 

Resorcinol 129-130° 

Pyrogallol 211-212° 

o-Nitrophenol 113-114° 

ESTERS AND ANHYDRIDES 

Almost invariably, esters are subjected to hydrolysis and the 
resultant acids and alcohols identified as such or otherwise con- 
verted into solid derivatives. When the corresponding amide is 
characteristic and fairly insoluble, the ester may usually be con- 
verted directly into the amide. Quantitative determination of 
the saponification equivalents are often of value when identify- 
ing esters. 

Amide Formation. — 5 cc. or 0.5 g. of ester is added to 10 cc. of concentrated 
ammonia water in a half-ounce bottle, and the suspension observed during 
several minutes with occasional shaking. If there is no evidence of rapid 
reaction, the flask is set aside for several hours or until the following day. 
When working with esters, extremely insoluble in water, a few cc. of alcohol 
may be added to facilitate reaction. The solid amide is filtered off and crystal- 
lized from water or alcohol. 

Anhydrides react with ammonia or amines exactly as do the esters except 
far more rapidly. 

AMINES 

A. Primary and secondary amines. 

1. Acetyl derivatives. 

2. Benzoyl derivatives. 

3. Benzenesulfonyl derivatives. 

4. Phthalyl derivatives. 

5. Picrates,' chloroplatinates, etc. 

^For the identification of alkaloid picrates see J. Am. Chem. Soc. 44, 
371 (1922). 



THE PREPARATION OF DERIVATIVES IGl 

B. Tertiary amines. 

1. Addition- products with alkyl halides. 

2. Substitution products such as nitroso derivatives, (if 

aromatic in nature). 

3. Picrates, chloroplatinates, etc. 

The acetyl derivatives are most often used for the preparation 
of derivatives of primary and secondary amines. Often they may 
be isolated in connection with the acetyl chloride test for amines 
(page 144) but usually it is best to prepare them from acetic anhy- 
dride. The reaction mixture is poured into water, warmed to 
decompose the excess of anhydride, cooled, and filtered. The 
product may be crystallized from water or dilute alcohol. 

The benzoyl and benzenesulfony] derivatives may be pre- 
pared in aqueous solution as outlined in Exp. 25, page 144. 

The formation of easily characterizable double salts with picric 
acid, chloroplatinic acid, chloroauric acid, and picrolonic acid is 
characteristic of many amines, including the tertiary members; 
these derivatives are of special importance in connection with the 
identification of quaternary ammonium compounds. The platinum 
and gold compounds are convenient for quantitative work. (See 
page 170.) 

OTHER NITROGEN COMPOUNDS 

The nitrogen-containing groups, other than the amino, that are 
commonly met are the amide, nitrile, imide, nitro, and azo. As a 
general procedure, individuals of the first three types are subjected 
to hydrolysis and those of the last two are converted into reduc- 
tion products. Definite instructions for these reactions have 
already been given in connection with the Classification Reactions, 
page 146, and they will therefore not be repeated here. 

In many instances these nitrogen compounds possess other 
reactive groups and the preparation of a characteristic derivative 
need not necessarily involve the nitrogen-containing group. For 
example, p-nitrotoluene may be derivatized by reactions involving 
(a) the nitro group, (6) the methyl group, and (c) the benzene 
nucleus. In this example, all three types of derivatives will be 
found to satisfy most of the requirements of good derivatives. 
Reduction by the procedure described on page 145 yields the vola- 
tile p-aminotoluene, m.p. 43°, which may be identified as such or 
converted into the acetyl derivative, m.p. 148°; oxidation of the 



162 QUALITATIVE ORGANIC ANALYSIS 

methyl group by the alkahne permanganate method described 
in the following section yields the characteristic p-nitrobenzoic 
acid, m.p. 237°; and nitration according to the methods outlined 
presently under toluene, yields 2, 4-dinitrotoluene. 

In view of the large number of individual compounds, par- 
ticularly of the mixed type, falling in this section, it seems best in 
order to conserve the limits of the chapter to consider only a few 
typical individual examples. 

Note and discuss derivatives and methods of preparation 
selected by Mulliken, Vol. II, for the compounds listed below. 
135 Salicyl amide. 
168 Phthalamidic acid. 
304 Hippuric acid. 

1468 Methyl-o-aminobenzoate. 

1462 Nitroglycerine. 

1568 Diphenylamine. 

1733 2, 4, 6-Trinitrotoluene. 

1787 Anesthesine. 

1946 Antipyrine. 

2555 Phthalimide. 

2619 Betaine. 

2636 Succin-a-naphthalide. 

2642 /-Tyrosine. 

2561 Caffeine. 

2651 Theobromine. 

2750 Phenyl isocj-anate. 

2781 Benzonitrile. 

2796 Nitrobenzene. 

2804 o-Nitrotoluene. 

2882 Azoxybenzene. 

2945 o-Nitroaniline. 

2989 ??-Nitrosodiethylaniline. 

2996 p-Nitrosodimethjdaniline. 

3016 m-Dinitrobenzene. 

3027 Benzoyl-o-nitroanilide. 

3126 2, 4-Dinitrophenol. 

3168 Picric acid. 

3191 p-Nitrosophenol. 
36 8-IIydroxyquinoline. 
72 2?-Nitrophenol. 
75 p-Nitrobenzylcyanide. 



THE PREPARATION OF DERIVATIVES 



163 



139 
164 
425 

148 
259 
290 J 



Nitrobenzoic acids. 



Aminobenzoic acids. 



HYDROCARBONS AND THEIR HALOGEN DERIVATIVES 

The saturated aliphatic hydrocarbons comprise the class of 
organic compounds most resistant toward the usual chemical 
reactions; the preparation of characteristic derivatives is there- 
fore a difficult matter. Moreover, this class of compounds is not 
ordinarily met in the form of individuals but rather in the form of 
complex mixtures, as, for example, in the various fractions from 
petroleum. Final tests applied in the identification of paraffin 
hydrocarbons, therefore, consist in the application of a variety of 
physical tests, such as boiling-point range, specific gravity, refrac- 
tive index, etc. Preliminary work, of course, must conclusively 
demonstrate the absence of appreciable amounts of compounds 
other than paraffin hydrocarbons. 

In connection with the identification of unsaturated hydro- 
carbons, valuable data are furnished by titration with bromine; 
the bromine addition products may often be used for melting-point 
or boiling-point determinations. Among the terpenes, the addi- 
tion products formed with bromine, halogen acid (usually HCl), 
and nitrosylchloride are of considerable value. The latter deriv- 
atives react with organic amines to yield nitrosylamines. (Cf. 
Rosenthaler, pages 22-28.) 



d- and Z-Limo 

nene 

Dipentene . . . . 

Pinene 

Camphene. . . , 



Boiling-point 
of Terpene 



175-6° 

177-8° 
155-6° 
160° 



Solid Derivatives of Mono- and Dicyclic 
Terpenes 



Melting-point 
of Hydro- 
chloride 



50° 

131° 
150-160° 



Melting-point 
of Bromide 



104° 
169-170" 



Melting-point 
of Nitroso- 
benzylamine 



93° 
109° 
122-3° 



164 QUALITATIVE ORGANIC ANALYSIS 

The halogen derivatives of aHphatic hydrocarbons may usually 
be conclusively identified by a combination of physical constants 
accompanied by a quantitative estimation, as outlined in Chapter 
XI, page 168. A variety of reactions for the preparation of solid 
derivatives are here available. 

1. Quaternary ammonium compounds. 

2. Solid esters. 

3. Substituted phthalimides. 

4. Reduction products. 

1. Quaternary Ammonium Compounds are prepared by mixing 
one part of the halogen compound with approximately the theo- 
retical proportion of a tertiary amine, such as dimethylaniline, 
pyridine, quinoline, trimethylamine, etc. The particular ter- 
tiary amine chosen should be one yielding a derivative with a con- 
venient melting-point. Occasionally the platinic chloride deriva- 
tive of the quaternary compound will be found to posses a definite 
melting-point. 

2. Solid esters may be prepared by a method exactly analogous 
with that given (page 158) for the identification of acids, except 
that now a salt of a known acid is chosen. The reaction will be 
found to be less smooth than that involving the use of p-nitro- 
benzyl bromide or phenacyl bromide, since certain halogen com- 
pounds may undergo loss of halogen acid with the resultant pro- 
duction of unsaturated compounds; the reaction velocity is also 
lower. 

3. Substituted phthalimides are prepared by heating ^ g. of 
potassium phthalimide with ^ cc. of a monohalogen compound 
usually in a sealed tube (150°-200°). The resultant derivatives 
are insoluble in dihde alkali, and thus can be separated readily 
from unchanged phthalimide. 

In the following table are listed a few substituted phthalimides. 
(Beilstein, II, 1799-1805; II,* 1051-1053.) 



Substance 


Melting-point 


/CO. 
C6H4< >N-CH3 

^CQ/ -CH2CH3 


132° 


78-9° 


-CH2CH2CH3 


66° 


. -CH(CH3)2 


85° 



Supplement of Vol. II. 



THE PREPARATION OF DERIVATIVES 165 

Substance Melting-point 

.CO. 
CsHZ \N-CH2CH2CH2CH3 65° 
^CQ/ -CH2CH(CH3)2 93° 

-CH2-CH = CH2 70-71° 
-CH2-C0H5 115-6° 

-CH2C6H4CH3 ortho 148-9° 
-CH2C6H4CH3 meta 117-8° 



AROMATIC HYDROCARBONS AND THEIR HALOGEN 
DERIVATIVES 

The two main reactions used in connection with the identifica- 
tion of aromatic compounds are (a) nitration and (b) oxidation of 
side-chains. Hydrocarbons of the condensed type yield definitely 
melting picrates. 

Nitration.^ — (a) Add I cc. of the unknown to a mixture of 1 cc. concen- 
trated HNO3 and 1 cc. concentrated H2SO4. Agitate the mixture and note 
any evolution of heat. Finally, warm gently over a small flame and agitate 
the mixture for at least one minute. After cooling somewhat, pour the reac- 
tion mixture upon a small amount of cracked ice. Separate the nitro com- 
pound and separate from any oily material by crystallization from alcohol. 

Comments: This procedure will yield m-dinitrobenzene from either 
benzene or nitrobenzene, the p-nitro derivatives from chlorobenzene, bromo- 
benzene, benzyl chloride, etc. Toluene yields an oily mixture of o- and 
p-nitro compounds and should be subjected to procedure (b). 

(b) Add about 3 or 4 drops of the hydrocarbon to 1 cc. of fuming nitric 
acid. Add 1 cc. of 5 per cent fuming sulfuric acid and warm gently over 
the free flame during about one minute. Isolate and purify the product 
as under example (a). 

Comments: Toluene, o-nitrotoluene, and p-nitrotoluene will yield 2, 4- 
dinitrotoluene in this reaction; mesitylene, m-xylene, p-xylene, and pseudo- 
cumene yield trinitro derivatives. 

Oxidation of Side-chains. — This reaction is applicable to a 
great variety of aromatic compounds; it is not feasible when the 
aromatic nucleus contains a phenolic or amino group either of 
which, when unprotected will lead to the destruction of the ring 
structure. 

1 Precaution. — Even when working with small quantities of material, 
special precaution must be observed in every nitric acid test, since certain 
organic substances may react violently. Losses of eyesight may easily result. 



166 QUALITATIVE ORGANIC ANALYSIS 

Procedure. — Into a 150 cc. r.b. flask, ^ place 75 cc. of water containing 
3 g. of KMn04. Add 1 cc. of the unknown and boil gently under the reflux 
condenser (why?) for about | to 2 hours, i.e., until the purple color of the 
permanganate has been replaced entirely by the brown of precipitated man- 
ganese dioxide. Filter the mixture and evaporate the filtrate to about one- 
half volume on the water-bath. Acidify to precipitate the organic acid, 
recrystallize from water or dilute alcohol, dry, and take melting-point. 

Comments: The yield is poor with such hydrocarbons as toluene, ethyl 
benzene, butyl benzene, etc., but is very satisfactory with the disubstituted 
products such as the nitrotoluene, the chloro- and bromo-toluenes, the xylenes, 
etc. When the side-chain consists of a — CH2OH or — CHO group, the 
yield will of course be better still and this is true also for the — CH2CI and 
— CHiBr side-chains. When reactive halogen is known to be present, about 
i g. NaoCOs should be added to the reaction-mixture. 

Compounds with somewhat more complex side-chains may behave some- 
what abnormally, for example, acetophenone yields C6H5COCO2H and naph- 
thalene yields some C6Hi-C02H-COC02H. In such special cases, the MnOa 
is not filtered from the reaction mixture but the latter is acidified directly. 
In acid solution, MnOo will oxidize quickly the above oxalyl derivatives to 
benzoic and phthalic acid, respectively. Any excess Mn02 is then removed 
by the addition of a little sodium bisulfite. 

Preparation of Picrates. — Dissolve 0.1 g. of hydrocarbon (naphthalene, 
phenanthrene, or acenaphthene) and 0.2 g. of picric acid in 5 cc. of boiling 
95 per cent alcohol. Allow the solution to cool gradually. Filter off the 
yellow crystals, RH-C6H2(N02)30H, and recrystallize from a small amount 
of alcohol. Dry on a clay plate and take melting-points. 

Substance Melting-point 

Picric acid 121° 

Naphthalene picrate 150° 

Phenanthrene picrate 143° 

Acenapthene picrate 161° 

1 A round-bottom flask is required since bumping may break an ordinary 
flask. A copper utensil avoids the difficult}' of "bumping." 



CHAPTER XI 
QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS 

It will seldom be necessary in this course to resort to methods 
of ultimate analysis, and it is for this reason that combustion 
methods for carbon, hydrogen, and nitrogen are omitted from this 
chapter. This is true also of the Carius determination for halogens 
and the fusion methods for sulfur, arsenic, and phosphorus. 
In dealing with compounds of unusual difficulty, the methods of 
ultimate analysis may have to be employed, but under such cir- 
cumstances the student is directed to other sources ^ where direc- 
tions will be found in more detail than would be justifiable here. 

Several of the qualitative methods and particularly the esti- 
mation of certain reactive groups, however, are of considerable 
value in connection with identification work, not merely in the 
first stages of an analysis but also in connection with confirmatory 
tests when the preparation of derivatives is not feasible. More- 
over, a considerable number of such tests involve simple volumetric 
methods and require comparatively little time when the standard- 
ized solutions are available. Some of the more adaptable methods 
are, therefore, given here but the student is encouraged to become 
familiar with more advanced treatments of the subject ^ that will 
supply a greater variety of methods together with valuable refer- 
ences to the original articles. 

Determination of Nitrogen by the Kjeldahl Method. — Most 
organic compounds in which nitrogen is present in non-oxidized 
form are decomposed when digested with sulfuric acid with the 
resultant formation of ammonium sulfate. The ammonia may 

^ Weyl, Meyer, Lassar-Cohn, etc. Some of the more elementary labor- 
atory manuals give excellent treatments of the subject. This is true especially 
of Gattermann's Practical Organic Chemistry, Noyes' Organic Chemistry for 
the Laboratory, and Fisher's Laboratory Manual of Organic Chemistry. 

^ For references, see the end of this chapter. 

167 



1G8 QUALITATIVE ORGANIC ANALYSIS 

then be liberated with a non-volatile alkali, distilled from the mix- 
ture into a known volume of standard acid, and determined volu- 
metrically by titrating the excess acid, 

A known weight (usually 0.300 g.) of the substance is placed in a 500 cc. 
Kjeldahl flask and dissolved in 25 cc. of pure concentrated sulfuric acid. Five 
grams of potassium sulfate and 0.25 g. of copper sulfate are added and the 
mixture gradually heated to boiling over a small flame and subsequently 
digested at the boiling temperature during one or two hours or until the liquid 
is practically colorless. 

The oxidized mixture is allowed to cool, diluted carefully with 250 cc. 
of distilled w^ater and a few chips of porous plate added. A 40 g. portion of 
solid stick NaOH c.p. is then carefully added to the cool solution and the 
flask immediately connected with the condensing apparatus, the receiving 
flask of which must be in place. After the caustic has dissolved, the solution 
is slowly distilled until at least 100 cc. of distillate has been collected. This 
should require about one-half hour. 

The receiving flask consists of a 250-cc. Erlenmeyer flask containing 30 cc. 
of standard 0.2 N. sulfuric acid and a few drops of congo red (or methyl 
orange) indicator. The tip of the exit tube should be immersed in the 
standard acid. After the distillation is complete, the excess acid is titrated 
with 0.2 N alkaU. 

Since some of the materials used in the analysis will contain traces of nitro- 
genous matter, it is necessary to run a blank determination and apply the 
correction to the values obtained with the unknown. 

The results are calculated either as percentage of nitrogen or according 

to the formula: 

^ . , „, . , Wt. of Sample X 1000 

Equivalent Weight ^ = - — — — — . 

Cc. Normal acid used 

DETERMINATION OF HALOGENS ^ 

Most organic halogen compounds including many of the more 
stable aromatic types are readily decomposed by metallic sodium 
in absolute alcohol. The halogen is then precipitated by the addi- 
tion of standard AgNOs solution and the excess of the latter 
determined by titration according to the Volhard method. 

A known weight of the organic compound (about 0.250 g.') is placed in 

^ This value will be equal to the formula weight if the molecule contains 
one nitrogen atom; when two or three nitrogens are present, the apparent 
molar weight wiU be one-half or one-third, respectively, of the actual molar 
weight. 

2 Stepanow, Ber. 39, 4056 (1906). Noycs Lab. Manual, 1916, p. 23. 

* If the substance is a liquid, the portion used in the specific gravity 
determination is utilized and therefore no additional weighing of sample is 
required. 



QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS 169 

a 100-cc. long-neck r.b. flask together with 35 cc. of absolute alcohol. The 
solution is heated to boiling under a condenser and 3.5 g. of metallic sodium 
added gradually to the boiling solution during about twenty minutes. Finally, 
the solution is heated for one-half hour longer, when the sodium should be 
dissolved. 

Cool the solution and add cautiously, through the condenser, 50 cc. of 
distilled water. Transfer the solution to a 250 cc. Erlenmeyer flask, acidify 
with nitric acid (chlorine-free), filter if necessary, and precipitate the silver 
halide by the addition of a slight excess of N/10 AgNOs. Add ferric alum 
as an indicator and titrate the excess AgNOa by means of N/20 thiocyanate 
solution. (If the halide is chlorine, the ppt. of AgCl should be filtered off 
before titrating with thiocyanate. Why?) 

In the calculation of results, use a formula analogous with that given 
above under the nitrogen determination. 

lonizable Halogen. — Substances yielding ionizable halogen 
when dissolved in water can usually be estimated directly without 
the digestion with sodium. The most common substances met in 
this class are the hydrochlorides of organic bases. 



ANALYSIS OF METALLIC DERIVATIVES 

Na, K, Ca, and Ba Salts. — About a 0.250 g. portion of the 
sample is weighed out in a tared platinum ^ or porcelain crucible 
and heated in a drying oven at 120° for several hours, until con- 
stant weight is attained. The loss in weight usually represents 
water of crystallization. Occasionally, substances are met that 
require drying at appreciably higher temperatures. 

The crucible is now heated over a small free flame' until all 
initial decomposition is complete. After cooHng, the residue is 
treated with two drops of concentrated sulfuric acid, heated very 
gently with indirect flame until fumes of SO3 cease to escape, 
and finally heated to dull redness until the residual sulfate is prac- 
tically white. (With sodium and potassium sulfates, the heating 
must be sufficiently low to prevent volatility.) The residual sul- 
fate, that may be contaminated with a trace of sulfide, is best 
treated with one more drop of H2SO4, and heated to constant 
weight. 

Ammonium Salts. — Ammonium salts may be estimated by the 
Kjeldahl procedure without requiring sulfuric acid digestion. 

^ Platinum is not used in the presence of phosphorus, arsenic, lead, etc. 
Why? 



170 QUALITATIVE ORGANIC ANALYSIS 

Silver and Platinum Salts. — In connection with identification 
work, silver salts of organic acids and platinic chloride double salts 
of organic bases are prepared, particularly when only small amounts 
of material are available for investigation. The silver salts are pre- 
pared by exactly neutralizing the organic acid with NaOH, adding 
the requisite amount of silver nitrate, filtering, washing thoroughly 
with water, and drying at 100°. The platinic chlorides are pre- 
pared by dissolving the organic base in hydrochloric acid, 
adding about ^ mole of chloroplatinic acid, filtering off the salt, 
(R-NH3)2PtCl6, and crystallizing from alcohol when feasible. 

A 0.200 g. portion of the dry salt is then gently ignited in a 
porcelain crucible and weighed either as metallic Ag or as metal- 
lic Pt. 

In addition to being of constant composition, the platinic 
chlorides of some organic bases possess definite melting-points and 
characteristic crystalline structures. The latter property, espe- 
cially, suggests their importance in micro-analysis. 

ESTIMATION OF UNSATURATION 

A number of the simple ethylene derivatives may be titrated 
quantitatively with bromine. The test is, of course, applied only 
when the previous classification reaction has shown that bromine 
is decolorized without appreciable substitution taking place. The 
weighed substance (about 1 g.) is dissolved in 25 cc. of carbon 
tetrachloride, the mixture cooled in a freezing bath, and titrated 
with a bromine solution of known strength (about N/2) until a 
faint bromine color remains. 

The following modified method, that of Hanus, is of general 
application and serves also in technical analysis for the deter- 
mination of the iodine numbers of natural products such as fats, 
fatty acids, waxes, etc. 

The iodine solution is prepared by dissolving 13 g. of iodine in 1000 cc. 
of glacial acetic acid and adding 3 cc. of bromine to the cold acetic acid solu- 
tion. 

A 0.200 g. sample is transferred to a 250 cc. glass-stoppered Erlenmeyer 
flask and dissolved in 10 cc. of chloroform. To this solution there is now 
added 25 to 50 cc. of the iodine solution (about 50 per cent excess should be 
used), and the mixture allowed to stand, with occasional shaking, for thirty 
minutes. 

The reaction mixture is next treated with 2 g. of KI dissolved in about 
10 cc. of water, shaken thoroughly, and 100 cc. of distilled water added. The 



QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS 171 

excess of iodine is titrated with standardized N/10 sodium thiosulfate solu- 
tion until only a faint iodine color remains. The solution is now again shaken. 
One cc. of starch paste is added, and the titration continued until the blue 
color just disappears. 

While the above determination is being carried out, a blank determi- 
nation is conducted in exactly the same manner. This is essential because 
changes in the acetic acid-iodine solution make it inadvisable to assign a 
definite normality factor to this solution. 

The iodine number of a substance represents the percentage of iodine 
(or its equivalent) absorbed by the sample. Thus when a sample weighing 
0.200 g. absorbs an equal weight of iodine, it possesses an iodine number 
of 100. 



ESTIMATION OF HYDROXYL 

The hydroxyl group is estimated best by indirect methods. 
The hydroxyl compound is converted into an acetyl, benzoyl, 
or analogous derivative and the resultant ester subjected to 
saponification according to the method described below for esters. 
The molar equivalent of the hydroxy compound is thus equal to 
the saponification equivalent of the ester minus the molecular 
weight of the acyl radical with a +1 correction for the hydrogen 
atom. In this determination, it is, of course, also essential to 
subject the original compound to saponification test. For example, 
the compound CHOH-CO2C2H5 will yield the corresponding 
I 
CHOH-CO2C2H5 

diacetyl derivative but upon saponification of the latter, four 
molecules of alkali will be involved. 

The reaction products of certain alcohols with phthalic anhj'- 

.CO2R 
dride, C6H4<^ , may be isolated and used for the determi- 

\CO2H 
nation of neutral equivalents. The molar weight of the radical 
R may thus be determined. 

ESTIMATION OF THE CARBONYL GROUP 

This determination is seldom required and consequently no 
detailed directions are given. The references at the end of this 
chapter should be consulted. The main methods are as follows : 

1. By choosing a hydrazine derivative of sufficiently high 
molecular weight, like /3-naphthylhydrazine, extremely insoluble. 



172 QUALITATIVE ORGANIC ANALYSIS 

solid hydrazoncs are obtained and these may be weighed directly 
after dryiiig in the oven. 

2. The carbonyl compound in alcohol is treated with a slight 
excess of hydroxylamine sulfate solution. A known amount, but 
no excess, of standardized alkali is now added. After completion 
of the reaction, the remaining hydroxylamine is,, titrated with 
standard acid using methyl orange. 

3. The aldehyde or ketone may be converted into the phenyl- 
hydrazone and the excess of reagent determined by measuring 
the volume of nitrogen gas liberated by Fehling's solution at the 
boiling temperature. The hydrazone is not attacked by this 
oxidizing agent. 

C6H5NHNH2+O -^ C0H0+N2+H2O 

4. Important quantitative methods in the sugar group are 
based upon the behavior of reducing sugars with Fehling's solution. 
The amount of reduction that has taken place, under certain 
specified experimental conditions, may be determined from the 
amount of CuoO formed, which may be estimated either gravi- 
metrically or volumetrically. In connection with identification 
of individual sugars, this method is however of little value. 

ESTIMATION OF THE CARBOXYL AND ESTER GROUPS 

The carboxyl group may be determined by direct titration 
according to the method suggested in the classification reactions 
in Chapter IX, Exp. 14. The saponification of esters, likewise, 
is illustrated in laboratory experiment No. 17. 

ESTIMATION OF ALKOXYL GROUPS 

The Zeisel method ^ is based upon the fact that alkoxyl groups, 
whether in ethers or esters, are decomposed by heating with strong 
hydriodic acid to yield alkyl iodides. The latter are absorbed 
in alcoholic AgNOa and estimated as Agl. 

/OCH3 /OH 

CgH4< +HI -> CcH4< +CH3I 

\CO2H \CO2H 

1 Internal. Cong. Applied Chcm. Ill, Vol. 2, p. 63 (1898). J. Chem. See. 
81, 318; 115, 193 (1919). 



QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS 173 



When the Zeisel method is appHed to compounds containing 
nitrogen, it must be remembered that alkyl groups on nitrogen may 
occasionally be partially replaced to yield alkyl iodides. On the 
other hand, under the influence of HI, an alkyl grOup might con- 
ceivably be transferred from oxygen to nitrogen. 

The apparatus ordinarily used in that shown in Fig. 12. 




Fig. 12. 

For the analysis of a 0.300 g. sartiple, the 50 cc. r.b. flask A is charged 
with 15 cc. of redistilled aqueous hydriodic acid (sp. g. 1.68), a chip of clay- 
plate and a trace of red phosphorus. It is connected with the small con- 
denser B containing water at about 40-60° which, in turn, is connected with 
three wash bottles C, D, and E. The first contains warm water and ^ g. of 
red phosphorus to remove HI and I2 vapors, while D and E contain 40 cc. 
and 20 cc. respectively of a saturated solution of AgNOa in absolute alcohol. 

Before proceeding with an analysis, a blank test is made. The flask A 
is heated to cause appreciable refluxing. A stream of CO2, purified by passing 
through aqueous AgNOa and next through HoSOj, is passed through the 
apparatus (but not through the HI solution) as indicated. No turbidity 
should be observed in the flask D during an interval of about 10 minutes. 

The flask A is now cooled, the sample introduced, and the heating and 
passing of CO2 repeated. A white precipitate of the silver iodide-silver 
nitrate double salt separates in flask D after about 10 minutes and the reac- 
tion is usually completed in 40 minutes. 

The silver nitrate solutions are now combined, diluted with several volumes 
of water, acidified with nitric acid, boiled gently for several minutes, and the 
silver iodide determined gravimetrically. 



174 QUALITATIVE ORGANIC ANALYSIS 

The above procedure is satisfactory with non-volatile unknowns. 
In dealing with appreciable volatile products, special precautions 
must be taken in adding the weighed sample and the water in the 
condenser B must be kept cold during the early stage of the heating. 

ESTIMATION OF THE AMINE GROUP 

1. The derivatives formed by the reaction of primary and 
secondary amines with phthalic anhydride, 

C6H4<; and C6H4< ^R 

\CO2H \CO2H 

may be isolated, purified by cr3^stallization from water or dilute 
alcohol, dried, and titrated against standard NaOH as in the deter- 
mination of neutral equivalents of other organic acids. By sub- 
tracting 148 from the neutral equivalent value, the equivalent 
weight of the amine is obtained. A modification of this method is 
outlined below. 

2. Many free aliphatic amines may be titrated directly with 
standard acid in the presence of methyl orange or congo red. 
Salts of weak bases (aryl amines) with strong inorganic acids 
(HCl, H2SO4, HNO3) may be titrated directly with standard 
alkali using phenolphthalein as an indicator. 

The above phthalic anhydride method for the estimation of 
the primary and secondary amine groups may be modified as 
follows : 

0.200 g. of pure phthalic anhydride ^ is placed in a dry 100 cc. glass- 
stoppered cylinder and dissolved in about 5 cc. of benzene. To this solution 
there is now added 0.100 g. of the amine under examination dissolved in 10 cc. 
of benzene or alcohol-free ether. The mixture is thoroughly shaken during 
several minutes. 27.0 cc. of N/10 NaOH is added and the solution again 
shaken for several minutes in order to insure decomposition of any excess of 
phthalic anhydride. A few drops of phenolphthalein are now added and the 
solution titrated to the neutral point with N/10 acid. Since 27 cc. of N/10 
alkali represents the exact amount required for neutralization of the phthalic 
anhydride, the amount of N/10 acid consumed serves for the calculation of 
the equivalent weight of the amine. 

Wt. of sample X 1000 



Equivalent Weight 



Cc. N/1 acid used 



1 With amines of low m. wt. (below 74), the amoimt of phthalic anhydride 
must be increased and a proportional volume of alkali used. 



QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS 175 

The above test possesses distinct advantages over the older 
acetic anhydride method. Phthahc anhydride is obtainable in 
practically 100 per cent purity and blank determinations are 
usually not required. Moreover, since the reagent is a solid, it 
may be weighed more conveniently. The method may experience 
a limitation in a few special instances where insoluble salts are 
formed between the organic acid and the amine; in such instances 
the alkali must be added slowly and in small portions so as to lib- 
erate the amine and permit complete reaction with the anhydride. 

REFERENCES 

Meyer: Analyse und Konstitutionermittelung organischer Ver- 

bindungen. 
Weyl: Methoden der organischen Chemie. 
Allen: Commercial Analysis. 
Sherman: Organic Analysis. 
Lassar-Cohn : Arbeits-Methoden. 

Meyer-Tingle: Determination of Radicals in Carbon Compounds. 
Vaubel: Methoden der quantitativen Bestimmung organischer 

Verbindungen. 
Kingscott and Knight: Methods of Quantitative Organic Analysis. 



CHAPTER XII 
EXAMINATION OF MIXTURES 

The ideal method to be followed in the identification of the 
components of a mixture consists in, first, separating the unknown 
into its pure individuals and, second, identifying each individual 
according to the method already outlined (Chapter VI). Only in 
exceptional instances will it be permissible to attempt an identi- 
fication of the constituent of a mixture without a previous sepa- 
ration. 

The laboratory work in this part of the course will include a 
study of two or three relatively simple mixtures, each consisting 
of from two to six components. The identification of these mix- 
tures will require a thorough mastery of the preceding work, espe- 
cially since it is impossible to outline a set of procedures that may 
be applied directly to the great variety of combinations that may 
be met. More or less specific instructions may be given, however, 
concerning the preliminary examination of mixtures. 

A thorough prelinmiary examination should always precede any 
attempt made to separate a mixture. — To the experienced analyst, 
certain " short-cuts " will always be apparent, but for the beginner 
and usually for the experienced chemist also, a thorough prelim- 
inary examination is by far the best *' short-cut " to be found. 
In the case of a liquid unknown, there is always the temptation to 
proceed immediately to a fractional distillation and in the case of a 
solid mixture we find too often that the first attempt at analysis 
has been a resort to the use of the wrong solvents. It is only after 
the preliminary examination that one can decide upon the most 
logical and satisfactory method for the final separation. Although 
these preliminary tests are usually similar for diff"erent mixtures, 
the final methods of separation will be difi'erent in every case, 
since it will then be possible to dispense with all unnecessary steps. 

176 



EXAMINATION OF MIXTURES 177 

In outlining methods for the preHminary examination, we shall 
limit ourselves to two types of mixtures: (a) water-insoluble and 
(b) water-soluble. Naturally, many mixtures will fall in an inter- 
mediate field, some of the ingredients being water-soluble and others 
insoluble in water. Alcoholic solutions of water-insoluble com- 
pounds furnish a very common example of this type. Frequently 
the solubility in water of certain ingredients will be appreciably 
affected by the presence of other compounds, particularly by sol- 
vents. It is felt, however, that a study of the common methods of 
attack of the two extremes will enable the student to deal effect- 
ively with intermediate types also. Occasionally, it may be 
necessary to conduct preliminary examinations on both the water- 
soluble and the water-insoluble parts of a mixture; such examina- 
tions are not conducted independently but the results found in 
the examination of one fraction are used to facilitate the study of 
the other. 

The greatest possibility of error in connection with the sepa- 
ration of mixtures lies in missing an ingredient which, although of 
importance, may be present only in traces and may require some 
special test. In actual technical work, such difficulties are only 
apparent since additional information concerning the source of 
the material and the use for which it is intended is usually avail- 
able. 

In connection with a study of mixtures, it is essential to keep 
in mind continually the possibility of interaction between the 
ingredients and especially the possibility of decomposition during 
the process of separation; for example, easily hydrolyzable esters, 
amides, and anhydrides may be met in the form of their decompo- 
sition products. Cases of doubt call for a study of the original 
sample. 

OUTLINE FOR THE PRELIMINARY EXAMINATION OF A 
MIXTURE 

(Record notes in the order outlined here) 

Mixtures of Type A. (Insoluble in Water.) 

I. Physical Characteristics. — Examine the unknown for color, 
odor, homogeneity, etc. In the case of a solid, it will often be 
possible to observe various forms of crystals (and especially so 
when a microscope is used) and often small fragments of the pure 



178 QUALITATIVE ORGANIC ANALYSIS 

individuals may be isolated mechanically. If this is possible, it is, 
however, no excuse for a variation in the following steps, since a 
more effective method of separation will usually be found. In the 
case of certain mixtures, as when a solid is in suspension in a liquid, 
or when dealing with two liquid layers, it is best to separate the 
mixture into two parts, filtering in the first instance and using the 
separatory funnel in the second. Tests should then be made upon 
each portion of the mixture. In such cases, it is to be expected 
that certain ingredients will be found in both parts of the mix- 
ture. 

II. Ignition Test. — Ignite a small amount of material on plat- 
inum foil or in a crucible and apply the usual observations, viz., 
fusion temperature, appearance of the flame, odor, presence of 
inorganic material, etc. 

III. Elementary Analysis. — Although analyses will be made on 
the fractions to be separated later, it is necessary to run also an 
elementary analysis on the original mixture; the result obtained 
may serve to detect an ingredient which might otherwise be over- 
looked. 

IV. Solubility Behavior. — The solubility tests differ from those 
applied to individual compounds in one essential point; it is neces- 
sary to determine whether any part of the mixture has dissolved. 
This is done by separating the solvent and examining it for dis- 
solved material by precipitation, extraction, or distillation meth- 
ods, or by combinations of such methods. Diminution of volume 
in liquid unknowns is occasionally of value. The following scheme 
is of value in connection with the application of solubility tests 
on a water-insoluble mixture. A one-gram sample will usually 
serve for these tests and the suction pipette, page 112, will be 
found of particular value in connection with the separations and 
extractions. All fractions are to be retained for later use. 

Fraction C will contain the water-insoluble basic compounds 
as well as amphoteric compounds; alkalinization will precipitate 
the former but not the latter. From fraction D the insoluble 
acids may be removed by acidification. How will you test for the 
amphoteric group? 

In order to secure reasonably sharp separations, it is well to 
apply two acid and alkaline extractions respectively. It is well 
also to wash fractions C and D with small portions of ether (Why?), 
although these ether washings may be discarded. Before precip- 



EXAMINATION OF MIXTURES 



179 



itating the organic bases and acids from fractions C and D, it is 
advisable to remove dissolved ether (Why?) by gentle warming. 



UNKNOWN. 



If Liquid, Remove any Volatile Solvent by 
Distillation on Water-bath 



Volatile 
Solvent 


Residue. Treat with Ether 


A 


Insoluble 

Part 

B 


Soluble in Ether. Treat with dilute HCl. 




Soluble Part 
C 


Ether Layer. Wash with a small 
volume of HoO. Treat with 
dilute KOH. 




Soluble Part 
D 


Ether Layer. Dry 
with a little Na2S04 
and evaporate to 
obtain indifferent 
compounds. 
E 



V. Subsequent Fractionation. — The various fractions obtained 
in connection with the solubility tests will not necessarily consist of 
individual compounds; each fraction may require further separa- 
tion, for example, D may consist of a mixture of acidic compounds 
and E of a mixture of neutral substances. Tests for homogeneity 
must therefore be applied to the individual fractions and, if neces- 
sary, a given fraction must be subjected to further separation. 
This is done usually in connection with the final separation of the 
main mixture. Suggested procedures will be discussed subse- 
quently and are also illustrated in the problems at the end of this 
chapter. 

VI. Outline of Plan. — Using the data obtained above, record 
in your notebook a list of possible homologous series present in the 
mixture and outline in your notebook a diagrammatic scheme for 
the separation of the mixture, submitting this to your instructor 
for his approval. 

VII. Proceed with the FinpJ Separation of the Mixture. — Use 
a weighed quantity of material and weigh the separate fractions 
obtained. 



180 QUALITATIVE ORGANIC ANALYSIS 

VIII. Identify the individuals isolated from the mixture by the 
steps previously outlined (Chapter VI) for the Identification of 
Individual Compounds. 



Mixtures of Type B (Water-soluble) 

I. Preliminary examination as described under Procedure A. 

II. Ignition Test. — Ignite a small amount of the material on 
platinum foil. If the substance does not burn readily, it may be 
an aqueous solution and whether or not this is the case will be 
indicated by the fact that the mixture is soluble in water but insol- 
uble in ether and possesses a low boiling-point. 

III. Elementary Analysis. — Precaution! Do not apply the 
sodium decomposition test to aqueous solutions! In such cases, 
reserve the elementary analysis until the individual fractions are 
being examined. The aqueous solution should be examined, how- 
ever, for inorganic radicals. 

IV. Solubility Behavior. — Apply the following tests to the 
aqueous solution: 

(a) Test aqueous solution with litmus and phenolphthalein. 

(b) Extract a small portion with ether, dry the latter with 
anhydrous Na^SO^ and evaporate on a watch glass, avoiding con- 
densation of moisture. 

(c) To a small portion, add HCl (unless the original is strongly 
acidic) and cool. Note evolution of gas, formation of precipitate, 
etc. Apply an ether extraction test to the acidified solution. 

(d) To a small portion, add KOH and cool. Observe color 
changes, evolution of gases, formation of precipitates, etc. Apply 
an ether extraction test to the alkaline solution. 

(e) Evaporate a cubic centimeter of the original aqueous solu- 
tion to dryness on the water-bath. Is a residue left? 

V. Distillation and Miscellaneous Tests.— Aqueous solutions 
should be subjected to the following distillation tests. This 
method of separation is particularly valuable in the examination 
of quite dilute (1 to 5 per cent) aqueous solutions. Any individ- 
ual volatile fraction may be fiu'ther concentrated bj^ redistillation. 

(o) To a portion of the original mixture, add NaOH and distill 
carefully. 



EXAMINATION OF MIXTURES 



181 





Non- volatile part. Add dilute H2SO4. Distill. 


Volatile Part 


If sulfuric acid causes 
acid. 


charring, use phosphoric 


Aqueous solution of: 


Volatile Part 


Non-volatile part 


Volatile Bases 


Volatile acids 




Volatile indifferents 


If distillate is neutral 


Contains K2SO4 with 


Alcohols 


or requires only a 


non-volatile part.This 


Aldehydes 


little N/10 alkali for 


non-vol. part may be 


Ketones 


neut. then volatile 


different from that 


If the sp. gr. of this dis- 


acids are absent. 


obtained by evapor- 


tillate is that of pure 




ation of the original 


water then this group 




solution. Why? 


is absent. How would 






the basic group be 






separated here from 






the indifferent? 







From the aqueous solution containing only the volatile indifferents, the 
latter may be salted out very effectively with K2CO3 unless the solution is too 
dilute. 

(6) Apply the phenylhydrazine test, the iodoform test, the 
FeCls test, the Br2 water test, etc., to small diluted portions of the 
original solution, or, better still, to the volatile part of the mix- 
ture. Be sure that these tests are applied under proper condi- 
tions, especially when applied to the original mixture. To illus- 
trate: Sulfates or oxalates might yield precipitates with phenyl- 
hydrazine, sulfites would decolorize Br2 water, etc. 



VI, VII, and VIII. (Proceed as Outhned for Mixtures of Type A.) 

After a mixture has been separated into certain groups (acidic 
group, indifferent group, etc.), it is necessary to determine by the 
application of the usual tests for purity whether these fractions 
consist of one or several individual compounds. 

When more than one individual is found in a given solubility 
group, additional operations are involved; subsequent separations 
are affected preferably by physical methods but, as a last resort, 
chemical methods which yield certain products in the form of 
derivatives may be required. 



182 QUALITATIVE ORGANIC ANALYSIS 

Physical methods of separating a given solubiHty fraction con- 
sist in the application of fractional distillation, fractional crystalli- 
zation, crystallization from solvents of various types, steam dis- 
tillation, sublimation, etc. Such operations are already familiar 
to the student but nevertheless abundant opportunity remains 
for the exercise of his .'ingenuity when relatively small amounts of 
material are available. 

Separation of the Acidic Fraction 

Among the acidic substances, separations may be affected occa- 
sionally by taking advantage of the variations in acidity. When 
excess carbon dioxide is passed into the solution of the acidic frac- 
tion in alkali, weak acids (when sparingly soluble in water), as, 
for example, certain amides, imides, phenols, etc., will be precip- 
itated while the stronger acids remain in solution. 

The principle of fractional precipitation is often of value when 
mere crystallization fails. The fraction is dissolved in alkali 
(dilute solution) and precipitated in fractions by the cautious addi- 
tion of dilute hydrochloric acid. In working with sparingly soluble 
acids, the solutions must be dilute and the acid added with vig- 
orous stirring in order to prevent the contamination of the product 
with salts of the organic acids. 

The use of insoluble salts (calcium, lead, etc.) may occasionally 
be used to advantage in the separation of mixtures of carboxylic 
acids. 

Among the volatile fatty acids, the Duclaux method is applica- 
ble not merely to identify the individual compounds but also to 
examine mixtures. An aqueous solution containing the volatile 
acidic fraction is distilled and the distillate collected in three frac- 
tions. If the first and third fraction, after dilution and deter- 
mination of the Duclaux values, yield checking results, proof is at 
hand that only one individual is present. If the first and third 
fractions differ considerably in the Duclaux values, a mixture is 
indicated. The results sometimes serve to identify the individual 
acids. 

Separation of the Amine Fraction 

The basic compounds, if solid, are subjected to crystallization 
and occasionally to fractional distillation; in this group, steam /I 



EXAMINATION OF MIXTURES 



183 



distillation may aid in effecting a separation. Fractional crys- 
tallization of certain salts of the amines is also of value; for this 
purpose the sulfates are utilizable but for special work the platinic 
chloride double salts are adaptable. 

It is often important to separate the three classes of amines, and 
this may be done by the application of the benzene sulfonyl 
chloride reaction. Cf . page 144. ^ • 

Mixture of Amines. 

Add aqueous KOH and C6H6SO2CI. After completion of reaction, filter or 

extract with ether. 



Soluble in aque- 
ous layer: 

Salt of sulfonyl 
derivative of 
prim, amine. 
Acidify to pre- 
cipitate deriv- 
ative of prim, 
amine. 



Ether layer: 

Tert. amine, sulfonyl derivative of sec. amine and some 
disulfonyl derivative of prim. Treat ether solution 
with dilute HCl. 



Soluble in HCl: 
tert. amine as 
hydrochloride. 



Soluble in ether layer: 
Sulfonyl derivative of sec. amine and 
disulfonyl derivative. Evaporate 
ether and warm with alcoholic 
KOH to decompose disulfonyl deriv- 
ative. Dilute with water. 



Soluble: 

Derivative of 
prim, amine. 



Insoluble: 

Derivative of sec. 
amine. 



A separation similar to the above can be based upon the reac- 
tion of the amines with phthalic anhydride, cf. page 62. A more 
common procedure consists in the treatment of the amine fraction 
with acetic anhydride, the separation of the tertiary amines by 
means of dilute acid and separation of the acetyl derivatives of the 
remaining members by crystallization. 



Separation of the Indifferent Fraction 

In work with the indifferent compounds, the physical methods 
already enumerated are generally of primary importance. Chem- 
ical reactions are also available. For example, a mixture boiling 



184 QUALITATIVE ORGANIC ANALYSIS 

at a fairly constant temperature (140-145°) consisted of a hydro- 
carbon and an ester; the latter was saponified and identified by 
the hydrolysis products and the hydrocarbon recovered as a pure 
individual. 

Cold concentrated sulfuric acid may serve often for the sep- 
aration of saturated hydrocarbons from their oxygenated deriva- 
tives. This reagent can be employed only when no decomposition 
of the dissolved material is observed. 

Dimethyl sulfate, used in connection with the classification 
reactions, may be utilized also for the separation of aromatic from 
saturated aliphatic hydrocarbons. Several treatments may be 
required to secure a complete separation. The aromatic hydro- 
carbon may be recovered from the dimethyl sulfate after saponi- 
fication of the latter. (Precautions, see page 135.) 

Mixtures Compounded by Nature 

Many mixtures met in technical work, particularly when from 
natural sources, are exceedingly complex. Fortunately, in such 
instances the analyst is often supplied with information concerning 
the source of the sample, the use for which it is intended, and the 
claims made for the product. A separation of ingredients usually 
is not essential to the identification; in fact, the analytical deter- 
mination (qualitative and quantitative) of one or more typical 
ingredients may furnish the required information. Moreover, in 
certain lines of technical analysis, an actual separation of indi- 
viduals is not necessary, but instead certain analytical procedures 
are applied directly to the mixture. For example, a sample of oil 
may be subjected to the following tests: 

(a) Specific gravity, 

(6) Melting or solidifying point, 

(c) Melting-point of acids obtained by saponification, 

(d) Behavior with solvents, 

(e) Hehner value (insoluble fatty acids), 
(/) Reichert-Meissel value (soluble acids), 
(g) Saponification value, 

{h) Iodine value, etc. 

In dealing with technical samples, the specialized literature of the 
subject must be consulted. Valuable information will be found in 



EXAMINATION OF MIXTURES 185 

Allen's Commercial Organic Analysis as well as in the advanced 
treatises dealing with food, plant, drug, dye, physiological, and 
toxicological analysis. 

Exercises. 

Outline in chart form procedures for the separation of the 
following three mixtures: 

1. An aqueous solution containing 1 per cent acetone, 5 per 
cent glucose, | per cent acetic acid, and 1 per cent aniline hydro- 
chloride. 

2. A homogeneous liquid containing 50 per cent ethyl alcohol 
and ether together with aniline, methylaniline, nitrobenzene, and 
m-dinitrobenzene. 

3. A solid consisting of salicylic acid, naphthalene, anthranilic 
acid, /3-naphthol, diphenylamine, and sucrose. 



PART C 

CLASSIFIED TABLES OF COMPOUNDS 

The plan for a Solubility Table was presented on page 24 of 
this text and will be found illustrated in more detail in the chart 
on the inside rear cover. In connection with a systematic identifi- 
cation of an unknown, the chart may be consulted after the com- 
pletion of the solubility tests since it may prove of aid in the choice 
of suitable classification reactions. The tables of individual 
compounds, however, should not be consulted until the completion 
of the tests and the systematic elimination of a considerable 
number of subgroups. 

In the tables which follow, approximately two thousand of the 
more common organic compounds are grouped in accordance 
with the plan above suggested. The tables are intended only for 
preliminary aid before proceeding to more advanced reference 
books and the student is offered no assurance that his unknown is 
included; his ability to identify unknowns is not limited to a few 
thousand compounds. 

In order to avoid too cumbersome a subdivision, certain sub- 
groups have been united, thus Group I, subgroups 1, 2, 3, and 4 
(neutral compounds) are listed in one table, the Hquids and solids 
being presented separately, and subgroups 5, 6, and 7 (acidic 
substances) are similarly grouped. 

Since solubility tests are of qualitative character only, certain 
compounds near the border line must be listed in more than one 
place to avoid error. For example, several of the compounds 
listed on page 189 will be reported normally " insoluble in water " 
according to the standards set in Chapter VIII. Such compounds, 
therefore, will be found also in the water-insoluble groups, e.g., 
Methyl isobutyrate, ethyl propionate, and n-propyl acetate are 
listed in V, 5; methyl propyl ketone and diethyl ketone in V, 3, etc. 

187 



188 QUALITATIVE ORGANIC ANALYSIS 

Halogen compounds are listed in all groups of the Solubility- 
Table, together with the corresponding unsubstituted compounds 
without being mentioned specifically as separate subgroups, except 
under Group VI. No nitrogen or sulfur compounds are included 
in Groups V and VI, but they are found in the other five groups; 
elementary analysis automatically relegates an indifferent suKur 
or nitrogen compound to Group VII. 

A few examples will illustrate these points. Ethylene chloro- 
hydrin is placed in Group I, 1, together with ethyl alcohol; 
the chlorobenzoic and nitrobenzoic acids will be found in Group IV, 
1, with other water-insoluble carboxyhc acids; and p-bromoanihne 
is included in Group III, 1, with other water-insoluble primary 
amines. p-Nitrobenzoic ethyl ester falls in Group VII, 1, and 
not in Group V, 5. At the stage of the procedure where the 
Solubility Table is consulted, it is only known that an indifferent 
nitrogen group is present; later tests will demonstrate the presence 
of another indifferent group (ester), but this need not interfere 
with the classification. m-Nitroacetanilide (m.p. 154°) possesses 
both a nitro and an amide group. It therefore falls under both 
Group VII, 1 and Group VII, 2 and the student should consult 
both groups; as a matter of fact, it will be found at both places, 
but this is not essential. 

The tables include practically all of the definite compounds 
available on the market with the exception of salts, dyes, and 
certain compounds without melting-points. (See, however, pages 
198-199.) In dealing with salts the organic and inorganic con- 
stituents are identified separately. 



CLASSIFIED TABLES OF COMPOUNDS 



189 



CLASSIFIED TABLES OF COMPOUNDS 

(Arranged in Accordance with the SolubiUty Table) 

GROUP I. SUB-GROUPS 1, 2, 3, and 4 

Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


13° 


0.894f 


Ethylene oxide 


21 


0.80&f 


Acetaldehyde 


32 


0.998f 


Methyl formate 


35 


0.719J^ 


Ethyl ether 


45 


0.862^ 


Methylal 


50 


0.806-2/ 


Propionaldehyde 


52 


0.84 


Acrolein 


54 


0.937f 


Ethyl formate 


56 


0.800Y 


Acetone 


57 


0.958^ 


Methyl acetate 


63-4 


0.794-Y 


Isobutyraldehyde 


64 


0.879" 


Dimethylacetal 


66 


0.792-2/ 


Methyl alcohol 


68-70 


0.882" 


Isopropyl formate 


73-4 


0.817-2/ 


n-Butyraldehyde 


77 


0.902-2/ 


Ethyl acetate 


78 


0.785-2/ 


Ethyl alcohol 


79 


0.937f 


Methyl propionate 


80 


O.8O520 


Ethyl methyl ketone 


81 


0.918f 


n-Propyl formate 


83 


0.94818 


AUyl formate 


83 


0.789-2/ 


Isopropyl alcohol 


83 


0.7802 6 


tert-Butyl alcohol, m. 25° 


87-8 


0.97322 


Diacetyl 


89 


0.850° 


Ethylal 


90 


1. 0692 2 


Methyl carbonate, m. 0° 


91 


0.917" 


Isopropyl acetate 


92 


O.Ollf 


Methyl isobutyrate 


93-4 


O.8O52" 


Isopropyl methyl ketone 


97 


0.850ff 


AUyl alcohol 


97 


0.804^ 


n-Propyl alcohol 


97-8 


1.05-.08 


Formalin (40% CH2O in water) 


98 


0.914" 


Ethyl propionate 


98 


1.512^ 


Chloral 


99 


O.8I922 


sec-Butyl alcohol 


101 


0.899-V'- 


n-Propyl acetate 


101 


0.97423 


Methyl orthoformate 


101-2 


0.812^5 


Methyl propyl ketone 


102 


0.834f 


Diethyl ketone 



190 



QUALITATIVE ORGANIC ANALYSIS 



GROUP I, SUB-GROUPS 1, 2, 3, and 4r— Continued 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


102° 


0.919f 


Methyl n-butyrate 


102 


0.81415 


ier(-Amyl alcohol 


103 


0.831-2/ 


Acetal 


103 


0.938 


AUyl acetate 


108 


0.80018 


Isobutyl alcohol 


116 


0.810-2/ 


w-Butyl alcohol 


118-9 


0.824" 


sec-Amyl alcohol 


119 


1.162i« 


Chloroacetone 


120 


1.2362 1 


a-Dichloroacetone 


124 


0.994-2/ 


Paraldehyde, m. 12° 


126 


0.9782 « 


Ethyl carbonate 


130 


0.810-2/ 


Isoamyl alcohol 


130 


1.235|§ 


Methyl chloroacetate 


132 


1.223" 


Ethylene chlorohydrin 


134-6 


1 . 154" 


Methyl pyruvate 


137 


0.97325 


Acetylacetone 


144 


1.118" 


Methyl lactate 


144 d. 




Methyl bromoacetate 


145 


0.898-2/ 


Ethyl orthoformate 


150-2 


I.719I8 


Ethylene bromohydrin 


154 


1.055" 


Ethyl lactate 


155 


1.060-/ 


Ethyl pyruvate 


155 


0.947-2/ 


Cyclohexanone 


161 


1 . 159-2/ 


Furfural 


162 


1.13217 


Trimethylene chlorohydrin 


164 


0.93125 


Diacetone alcohol 


167 




Glycolic acetal 


169 


1.07311 


Methyl acetoacetate 


170 


1 . 135f § 


Furfuryl alcohol 


172 


0.96715 


Pinacone m. 35° 


174 


2.65217 


Bromal 


176 


1.3661'' 


Glycerol a-dichlorohydrin 


181 


1.16015 


Methyl malonate 


182 




/3-Hydroxj'ethyl acetate 


182 


1.380" 


Glycerol /3-dichlorohydrin 


186 


1.0792/ 


Ethyl oxalate 


191 


1.0522 


Methyl levulinate 


195 


1.11725 


Methyl succinate, m. 18° 


207 


1.057-1/ 


7-Valerolactone 


208 


1.108" 


/3- Angelica lactone 


210 


1.07019 


Trimethylene glycol diacetate 


100-110/185 mm. 




Trimethylene bromohydrin 


258 


1.16111 


Triacetin 


260 


1.17615 


Diacetin 






CLASSIFIED TABLES OF COMPOUNDS 



191 



GROUP I. SUB-GROUPS 1, 2, 3, and 4 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


12° 


124° 


Paraldehyde 


18 


195 


Methyl succinate 


25 


83 


tert-Butyl alcohol 


35 


172 


Pinacone 


44 




Bromal alcoholate 


48 


280 


Methyl tartarate 


53 




Bromal hydrate 


55 


115 


Chloral alcoholate 


56 




Pinacone hydrate 


59 


97 d. 


Chloral hydrate 


79 


284 d. 


Methyl citrate 


83-4 




Benzoyl carbinol 


86 




o-Hydroxybenzyl alcohol 


86 




Diglycolide 


116 




Benzoquinone 


128 


255 


Lactide 



GROUP I. SUB-GROUPS 5*, 6, and 7 
Liquids 



BOILING-POINT 


SPECIFIC-GRAVITY 


NAME OF COMPOUND 


32° 


0.998f 


Methyl formate 


54 


0.948f 


Ethyl formate 


55 


1 . 105-2^ 


Acetyl chloride 


57 


0.958f 


Methyl acetate 


60 


1.0621" 


Chloromethyl ether 


63-4 




Oxalyl chloride 


71 


1.2361 ^ 


Methyl chloroforraate 


79 




Chloromethylethyl ether 


80 


1.064-Y- 


Propionyl chloride 


81 


1.529 


Acetyl bromide 


92 


1.017-2/ 


Isobutyryl chloride 


94 


1.139|§ 


Ethyl chloroformate 


97 




a-Chloroethyl ether 


100 


1.245f 


Formic acid 


100 


1.028-2/ 


n-Butyryl chloride 


105 


1.495" 


Chloroacetyl chloride 


105 


1.31520 


a, a'-Dichloromethyl ether 


115 


0.989-2/ 


Isovaleryl chloride 


116 


1.13712 


a, a'-Dichlorodiethyl ether 



* Aldehydes (see I, 2) may also show acid reaction due to the presence of 
oxidation products. 



192 



QUALITATIVE ORGANIC ANALYSIS 



GROUP I. SUB-GROUP 5, 6 and 7— Continued 


BOILING-POINT 


SPECIFIC GRAVITY 


NAME OP COMPOUND 


118° 


1.054-1^ 


Acetic acid, m. 16° 


127 (?) 


1.913» 


Chloroacetyl bromide 


127 


1.908" 


Bromoacetyl chloride 


138 


1.079^^ 


Acetic anhydride 


140 


1.062Y 


Acrylic acid 


140 


0.994f^ 


Propionic acid 


144 d. 


1.13911 


Propiolic acid 


149 


2.31721 


Bromoacetyl bromide 


155 


0.950^/ 


Isobutyric acid 


163 


0.960-1-^ 


n-Butyric acid 


168 


1.0171= 


Propionic anhydride 


165 d. 


1.28818 


Pyruvic acid 


169 d. 


1.018^5 


Isocrotonic acid 


176 


0.93120 


Isovaleric acid 


186 


1.28" 


a-Chloropropionic aicd 


189 


1.57213 


Dichloroacetic acid 


190 d. 


1.41215 


Succinyl chloride, m. 16° 


205 




a-Bromopropionic acid, m. 24° 


250 d. 


1 . 139-2/ 


Levulinic acid 



GROUP I. SUB-GROUPS 5, 6 and 7 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


13° 


165° d. 


Pyruvic acid 


16 


118 


Acetic acid 


16 


190 d. 


Succinyl chloride 


24 


205 


a-Bromopropionic acid 


33 


250 d. 


Levulinic acid 


42 




/3-Chloropropionic acid 


42 


180 


Phenol 


50 


208 


Bromoacetic acid 


54 


163 


Methyl oxalate 


57 


195 


Trichloroacetic acid 


58 


288 d. 


Orcinol (hydrate) 


61-2 




/3-Bromopropionic acid 


63 


185 


Chloroacetic acid 


64 


227 d. 


a, j3-Dibromopropionic acid 


66 


d. 


Cyanoacetic acid 


72 


182 


a-Crotonic acid 


78-9 


d. 


Glycolic acid 


82 




/3-Iodopropionic acid 


84 




lodoacetic acid 



CLASSIFIED TABLES OF COMPOUNDS 



193 



GROUP I. SUB-GROUPS, 5, 6 and 7— Continued 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


96° 


285° d. 


Phenoxyacetic acid 


100-10 d. 




Peracetic acid 


104 


245 d. 


Catechol 


105 


272/ 100 mm. 


n-Pimelic acid 


106 


263 d. 


Chlorohydroquinone 


107 


289 


Orcinol (anhydrous) 


110 




Bromohydroquinone 


110 


280 


Resorcinol 


111 


d. 


Ethylmalonic acid 


117 d. 




Benzylmalonic acid 


118 




dZ-Mandelic acid 


124 




Trichlorolactic acid 


124 




Toluhydroquinone 


130 


d. 


Maleic acid 


133 




( d-Mandelic acid 
I ^Mandelic acid 




133 


293 d. 


Pyrogallol 


133 d. 


d. 


Malonic acid 


135 d. 




Methylmalonic acid 


150 




Protocatechuic aldehyde 


169 


285 


Hydroquinone 


178-9 




Acetylenedicarboxylic acid 


189 


235 d. 


Succinic acid 


218 




Phloroglucinol 



GROUP I. SUB-GROUP 8 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OP COMPOUND 


-6° 


0.699-1" 


Methylamine 


3.5 


0.662-5 


Trimethylamine 


7 


0.686-« 


Dimethylamine 


19 


0.68915 


Ethylamine 


33 


0.69018 


Isopropylamine 


49 


0.71820 


n-Propylamine 


55 


0.71215 


Diethylamine 


58 


0.76915 


Allylamine 


63 


1820 


scc-Butylamine 


68-9 


0.73615 


Isobutylamine 


76-7 


0.74215 


n-Butylamin2 


95 


0.75018 


Isoamylamine 


103 


0.76619 


n-Amylamine 


105 


0.860^ 


Piperidine 


110 


0.74315 


Di-n-propylamine 



194 



QUALITATIVE ORGANIC ANALYSIS 



GROUP I. SUB-GROUP Sr-Continued 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


111° 




Diallylamine 


116 


0.97611 


Pyridine 


129 


0.949J^ 


a-Picoline 


133 




/3-DimethyIaminoethyl alcohol 


134 


0.8620 


Cyclohexylamine 


143-50 


0.928^* 


Piperylhydrazine 


161 




/3-Diethylaminoethyl alcohol 


184 


0.986i| 


Benzylamine 


189 


0.920* 


7-Diethylaminopropyl alcohol 


250 


1.011-2/ 


Z-Nicotine 



GROUP I. SUB-GROUP 8 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


41-2° 


143°/i8min. 


Cyanamide 


63 


282 


TO-Phenylenediamine 


80 d. 




2, 4-Diaminophenol 


85 




A^-Methyl-p-aminophenol 


102 


256 


o-Phenylenediamine 


104 


145 


Piperazine 


122 




m-Aminophenol 


140 


267 


p-Phenylenediamine 


170 




o-Aminophenol 



GROUP I. 



SUB-GROUP 9 

Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OP COMPOUND 


17° 


0.90015 


Ethyl nitrite 




65 di 


1.217^ 


Methyl nitrate 




81 


0.789^5 


Acetonitrile 




87 


1.116^= 


Ethyl nitrate 




97 


0.7802 


Propionitrile 




101 


1.1441s 


Nitromethane 




107-8 




Isobutyronitrile 




120 




Acetone cyanohydrin 




152 d. 


0.920|f 


Ethyl methyl ketoxime 




182 d. 




Lactonitrile 




192-5 d. 


1.337-V- 


Formamide, m. 3° 




222 


1.02411 


Formyl piperidine 




226 


1.011» 


Acetyl piperidine 




286 


0.99515 1 


Trimethylene cyanide 





CLASSIFIED TABLES OF COMPOUNDS 

GROUP I. SUB-GROUP 9 

Solids 



195 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


46° 


284° 


Formanilide 


47 


114 


a-Acetaldoxime 


50 


184 


Ethyl carbamate (Urethane) 


52 


177 


Methyl carbamate 


54 


265 d. 


Succinonitrile 


59 


195 


n-Propyl carbamate 


60 


135 


Acetoxime 


61 


215-20 d. 


Trichlorolactonitrile 


74-5 




Diacetylmonoxime 


79 


213 


Propionamide 


81-2 


d. 


Phenyl hydroxj'lamine 


82 


222 


Acetamide 


113 




Antipyrine 


114 




Chloralformamide 


115 


216 


n-Butyramide 


125-6 


287 


Succinimide 


128 


216 


Isobutyramide 



GROUP I. SUB-GROUP 10 
Liquids 



MELTING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


36° 
93 

188 


0.839-^"- 

1.0741" 
1.3315 


Ethyl mercaptan 
Thioacetic acid 
Methyl sulfate 



GROUP I. SUB-GROUP 10 
Solids 



MELTING-POINT 




NAME OF COMPOUND 


78° 

83-^ 
109 subl. 




Allyl thiocarbamide 
Benzenesulfinic acid 
Dimethyl sulfone, b. 238° 



196 



QUALITATIVE ORGANIC ANALYSIS 



GROUP II. SUB-GROUP 1 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


18° 


119°/l2min. 


d/-Lactic acid 


43 


255 


a-Hydroxybutyric acid 


79 




Glycolic acid 


80 




Citraconic acid 


97 


302 d. 


Glutaric acid 


100 




Citric acid (hydrated) 


100 




Z-Malic acid 


101 




Oxalic acid (hydrated) 


130 




Maleic acid 


132 




dWVIalic acid 


140-3 




i-Tartaric acid 


153 




Citric acid (anhydrous) 


161 




Itaconic acid 


169 




d-Tartaric acid 


185 


235 d. 


Succinic acid 


189 




Oxalic acid (anhydrous) 


190 d. 




Aconitic acid 


205-6 




d^Tartaric acid 


212 d. 




Mucic acid 



GROUP II. SUB-GROUP 2 

Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


188° 


1.0402 


Propylene glycol 


197 


1.113|f 


Ethylene glycol 


210-5 d. 


1.338" 


Glycerol a-chlorohydrin 


216 


1.05218 


Triraethylene glycol 


220-40 




Glycerol a-bromohydrin 


260 


1.17911 


Diacetin 


260-70 


1 -22111 


Monoacetin 


290 d. 


1.260-2/ 


Glycerol 



CLASSIFIED TABLES OF COMPOUNDS 

GROUP II. SUB-GROUP 2 
Solids 



197 



MELTING-POINT 




NAME OF COMPOUND 


85-90° 




Dextrose (hydrated) 


95 




Laevulose (d-Fructose) 


95-7 




Glycolic aldehyde 


95-105 




Rhamnose 


110 d. 




d-Glucosamine 


110-20 




Raffinose (hydrated) 


118-9 




Raffinose (anhydrous) 


132 




d-Mannose 


144-5 




i-Xylose 


146 




Glucose 


160 




Z-Arabinose 


165 




a-Methyl-d-glucoside 


166 




d-Mannitol 


170 




d-Galactose 


171-2 subl. 




Polyoxymethylene 


175 




Helicin (glucoside) 


178 d. 




Inulin 


185 




Saccharose 


201 




Salicin 


203 d. 




Lactose 


214 


# ■ 


Amygdalin 


225 




t-Inosite 


234 




d-Quercite 


240° d. 




Glycogen 


253 




Pentaerythrite 


d. 




Isomaltose 


d. 




Maltose 






Dextrins 



(Some glucosides are listed under V, 1.) 
GROUP II. SUB-GROUP 3 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 





171° 


/3-Aminoethyl alcohol 




286 


Trimethylene cyanide 


3° 


192-5 d. 


Formamide 


10 


116 


Ethylenediamine 


44 




Piperazine hydrate 


54 


265 d. 


Succinonitrile 



198 



QUALITATIVE ORGANIC ANALYSIS 
GROUP II. SUB-GROUP S— Continued 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


59° 




Triacetoneamine (hydrate) 


62 




Tetramethyl ammonium hydroxide 


63 


282° 


m-Phenylenediamine 


79 


213 


Propionamide 


80 d. 




2, 4-Diaminophenol 


82 


222 


Acetamide 


91-4 




Acetaldehyde ammonia 


101-2 


d. 


Methyl urea 


102 


256 


o-Phenylenediamine 


104 


145 (?) 


Piperazine 


105 




Dicyanodiamine (guanyl urea) 


nod. 




(/-Glucosamine 


113 




Antipyrine 


115 


216 


n-Butyramide 


122 




7M-Aminophenol 


125-6 


287-8 


Succinimide 


128 


216 


Isobutyramide 


132 




Carbamide (urea) 


140 


267 


p-Phenylenediamine 


170 




o-Aminophenol 


170 




Malonamide 


180 




s-Acetyl methyl urea 


190 d. 




Biuret 


190 d. 




Tetraethyl ammonium hydroxide 


195 d. 




^/-Alanine 


205 




Dicyanodiamide 


216 




Hydantoin 


218 




Acetyl urea 


226 d. 




( d-Asparagine 
\ Z-Asparagine 


232 d. 




GlycocoU 


232-40 d. 




Choline 


234 




Caffeine 


242 d. 




Succinamide 


243 




Parabain 


220+subl. 




a-Aminoisobutyric acid 


270 d. 




Z-Aspartic acid 


280 




Hexamethylenetetramine 


d. 




Barbituric acid 
Creatinine 






Guanidine 






Alloxan 






Betain 



CLASSIFIED TABLES OF COMPOUNDS 



199 



GROUP II. SUB-GROUP 4 

Solids 



MELTING-POINT 




NAME OP COMPOUND 


43-4° 




Benzenesulfonic acid (hydrate) 


65 




Benzenesulfonic acid (anhydrous) 


78-9 




/3-Naphthalenesulfonic acid (trihydrate) 


85 




Sulfoacetic acid 


85-90 




a-Naphthalenesulfonic acid 


92 




p-Toluenesulfonic acid 


100+ 




2, 5-Dichlorobenzenesulfonic acid 


120 




1, 2, 5-Sulfosalicj^lic acid 


122 d. 




2-Naphthol-6-sulfonic acid 


170 d. 




l-Naphthol-4-sulfomc acid 


170-4 




Thiourea 


195 d. 




d-Camphorsulfonic acid 






p-Phenolsulfonic acid 






/3-Naphthalenesulfonic acid (anhydrous) 


259 




p-Sulfobenzoic acid 






2-Naphthol-3, 6-Disulfonic acid 






2-Naphthol-6, 8-Disulfonic acid 


• 




Many other sulfonic acids, alkyl sulfuric 
acids, etc., usually met as salts. Cf. 
List in Eastman Catalogue of Organic 
Chemicals. 



200 



QUALITATIVE ORGANIC ANALYSIS 

GROUP III. SUB-GROUPS 1, 2, 3 

Liquids 



BOILING POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


89° 


0. 72511 


Triethylamine 


110 


0.73625 


Di-n-propylamine 


150-5 


0.809^5 


Triallylamine 


153 


0.750|f 


Tri-n-propylamine 


160 




Di-n-butylamine 


170 


0.8442 


d-Coniine 


183 


1.02111 


Aniline 


180-5 




n-Octylamine 


185 


0.929-^ 


Dimethyl-o-toluidine 


185 




Methyl benzylamine 


185 




Dimethyl benzylamine 


187 


0.76611 


Diisoamylamine 


192 


0.985ff 


Methylaniline 


193 


0.958^ 


Dimethylaniline 


199 


0.996ff 


o-Toluidine 


199 




Ethyl benzylamine 


201 




Ethylmethylaniline 


203 


0.989^ 


OT-Toluidine 


205 


0.963^ 


Ethylaniline 


205 


0.8620 


Z-Menthylamine 


207 


1.213^ 


o-Chloroaniline 


208 




AT-Methyl-p-toluidine 


210 


0.92920 


Dimethyl-p-toluidine 


211 


0.77820 


Tri-n-butylamine 


212 


0.91815 


1, 3-Dimethyl-4-aminobenzene 


215 


0.980^5 


1, 4-Dimethyl-2-aminobenzene 


218 


0.935^ 


Diethylaniline 


lOl-2/io mm. 




AT-Ethyl-p-toluidine 


124/i6mm. 




A''-Ethyl-o-toluidine 


220-5 


1.098^5 


o-Anisidine (o-Methoxyaminoben- 

zene) 


222 


0.949^8 


n-Propylaniline 


229 


0.96218 


Mesidine 


229 




o-Phenetidine 


230 


1.216^ 


?n-Chloroaniline 


236 




n-Butylaniline 


129/13 mm. 




Methyl A'^-methylanthranilate 


239 


1.09520 


Quinoline 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP III. SUB-GROUPS 1, 2, ^— Continued 



201 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


240° 


1.099-2^ 


Isoquinoline, m. 24° 


240 




3- Bromo-4-aminotoluene 


241-45 


0.91020 


Di-n-propylaniline 


139-40/15 mm. 




Di-n-butylaniline 


246 


1.101^° 


Quinaldine 


245-50 


1 -05611 


Tetrahydroquinoline 


250 




o-Bromoaniline, m. 31° 


251 


1.5822 


/ra-Bromoaniline, m. 18° 


254 


0.928J^ 


Isoamylaniline 


254 


1.061^5 


p-Phenetidine 


258 


1.068^ 


6-Methyl quinoline 


250-60 d. 


1.16815 


Methyl anthranilate 


260-5 




Ethyl anthranilate, m. 13° 


264 


1.06115 


2, 4-Dimethyl quinoline 


288 




Benzyl ethylaniline 


293 




Methyl a-naphthylamine 


294 




Ethyl TO-aminobenzoate 


296 


I.O48-24O 


Methyl diphenylamine 


298 


1.06715 


Benzylaniline 


300 


1. 03311 


Dibenzylamine 


304-5 d. 


1.15420 


6-Methoxyquinoline 


305-6 




Benzyl methylaniline 



GROUP III. SUB-GROUPS 1, 2, 3 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


13° 


2600 


Ethyl anthranilate 


15 


215-20 


Amino-p-xylene 


18 


251 


m-Bromoaniline 


20 


250 


Tetrahydroquinoline 


24 


240 


Isoquinoline 


24.5 


135/]5mm. 


Methyl anthranilate 


25-7 




m-Iodoaniline 


26 


240 


3- Bromo-4-aininotoluene 


28 


140/10 mm. 


6-Methoxyquinohne 


31 


250 


o-Bromoaniline 


32 


298 


Benzylaniline 



202 QUALITATIVE ORGANIC ANALYSIS 

GROUP III. SUB-GROUPS 1, 2, 3— Continued 



MELTING-POINT 


BOILING-POINT 


NAMK OF COMPOUND 


41° 


262° 


l-Dimethylamino-4-aminobenzene 


45 


200 


p-ToIuidine 


48 




Tetramethyl p-phenylenediamine 


49 


226 


1, 2, 4-Xylidine 


50 


300 


a-Naphthylamine 


51 




Procaine base 


52 


253-4 


Indol 


56 




o-Iodoaniline 


57 


243 


p-Anisidine 


58 


260 


4-Phenyl morpholine 


60 


260-5 


2, 6-Dimethyl quinoliae 


60 


280-5 


m-Nitrodimethylaniline 


62 





p-Iodoaniline 


63 


283 


m-Phenylenediamine 


63 


245 


2, 4-DichloroaniIine 


64 




Diphenylethylenediamine 


66 




p-Bromoaniline 


68 


235 


Pseudocumidine 


70 


300 d. 


Dibenzylaniline 


70 


232 


p-Chloroaniline 


71 




o-Nitroaniline 


72 




2-Nitro-p-toluidine 


73 




p-Dimethylaminobenzaldehyde 


74 




Ethyl phenylcinchoninate 


75 


266 


8-Hydroxyquinoline 


74-6 


165/30 mm. 


p-Dimethylaminophenol 


75-80 




Benzamidine 


77 


262 


s-Trichloroaniline 


79 




2, 4-Dibromoaniline 


82 


300+ 


/3-Naphtha quinaldine 


84 




p-Nitrosodiet hylaniline 


85-90 




o-Methylaminophenol 


85 




p-MethylaminophenoI 


85 


265-8 


m-DimethylaminophenoI 


85 




p-Nitroscdimethylaniline 


86-8 




2, 4-Diaminochlorobenzene 


88-90 




pp'-Diaminodiphenylmethane 


89 




Ethyl-p-aminobenzoate 


90-1 




Tetramethyldiaminodiphenyl- 






methane 



CLASSIFIED TABLES OF COMPOUNDS 203 

GROUP III. SUB-GROUPS 1, 2, 3— Continued 



MELTING-POINT 


BOILING-POINT 


91° 




91 




95 




98 




99-100 




102 


260 


102 


256 


106 


293-5 


107 




107 


360+ 


111-2 


300 


114 


285 


114 




114+ 




114-6 




115 




116 




117 




120-1 




122 




125 


360 


126 




127 


400 


127 




129 




129 




130 d. 




136 




138 




140 


267 


141 




144 




144 




145 




147 




147 




149 




155 




162 




163 





NAME OF COMPOUND 



Tribenzylamine 

6-Nitro-o-toluidine 

3-Nitro-o-toluidine 

Z-Cocaine 

2-Amino-5-azotoluene 

Methyl acetanilide 

o-Phenylenediamine 

p-Aminoacetophenone 

4-Nitro-2-aminotoIuene 

Acridine 

/3-Naphthylamine 

m-Nitroaniline 

3-Nitro-p-tolmdine 

p-Nitrosomethylaminobenzoate 

p-Nitrosomethylaniline 

Atropine (dZ-Hyoscyamine) 

3-Nitro-4-aminotoluene 

p-Dimethylaminoazobenzene 

s-Diphenylethylenediamine 

TO-Aminophenol 

p-Aminoazobenzene 

Phenylglycine 

Benzidine 

5-Nitro-2-aniinotoluene 

Methyleneaminoacetonitrile 

o-Tolidine 

Leucomalachite green 

Picolinic acid 

2, 6-DinitroaniIine 

p-Phenylenediamine 

Orthoform 

Anthranilic acid 

2-Nitro-l-aminonaphthalene 

a-Triphenylguanidine 

p-Nitroaniline 

Papaverine 

6-Nitroquinoline 

Z-Codeine 

p-Aminoacetanilide 

p-Nitrodimethylaniline 



204 QUALITATIVE ORGANIC ANALYSIS 

GROUP III. SUB-GROUPS 1, 2, S— Continued 



MELTING-POINT 




NAME OF COMPOUND 


163° 




Diphenylpiperazine 


164 




6-Nitroquinaldine 


170 d. 




di-a-Amino-n-caproic acid 


170 




o-Aminophenol 


171 




Quinidine (dextro) 


171-3 




Diacetyl morphine 


173 




5-Amino-o-cresol 


174 




Tetramethyldiaminobenzophenone 


174 




w-Aminobenzoic acid 


175 




Quinine (iBevo) 


176 




Narcotine (lajvo) 


178 




Brucine (Isevo) 


180 




2, 4-Dinitroaniline 


184 d. 




p-Aminophenol 


186 




p-Aminobenzoic acid 


199 




2-Hydroxyquinoline 


205 (180) 




Veratrine 


207 




Cinchonidine 


234 d. 




d- and ^Asparagine 


228-30 




Nicotinic acid 


230 




Quinolinic acid 


235 




Caffeine 


250 




Morphine (Isevo) 


250-5 




i-Aminoanthraquinone 


256 subl. 




dZ-Phenylaminoacetic acid 


263+ d. 




di-Phenylalanine 


265 




Cinchonine (dextro) 


268 




Strychnine (laevo) 


302 




2-Aminoanthraquinone 


280-300 d. 




p-Aminobenzenesulfonic acid (Sul- 
fanilic acid) 


310 subl. 




Isonicotinic acid 


314-8 d. 




Z-Tyrosine 


d. 




5-Aminosalicylic acid 






Creatin 
Melamine 


subl. 




fW-a-Aminocaprylic acid 


subl. 




<iZ-«-Amino-7i-valeric acid 






Guanine 



CLASSIFIED TABLES OF COMPOUNDS 



205 



GROUP III. SUB-GROUP 4 
Liquids 



BOILING-POINT 


MELTING-POINT 


NAME OF COMPOTJND 


227° d. 
243 


17° 


as-Methylphenylhydrazine 
Phenylhydrazine 



GROUP III. SUB-GROUP 4 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


44° 

61 
106 

157 d. 
210 d. 
220-5 d. 


220°/40mm. 

240-4 d. 


as-Diphenylhydrazine 

p-Tolylhydrazine 

p-Bromophenylhydrazine 

p-Nitrophenylhydrazine 

Anthraquinonylhydrazine 

p-Hydrazinobenzoic acid 



206 



QUALITATIVE ORGANIC ANALYSIS 



GROUP IV. SUB-GROUP 1 

Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


176° 


0.9312 


Isovaleric acid 


185 


0.94120 


n- Valeric acid 


191 


0.97815 


n-Butyric anhydride 


205 




a-Bromopropionic acid m. 24° 


205 


0.929^ 


n-Caproic acid 


207 


0.925-2J1 


Isocaproic acid 


212-7 d. 


1.5415 


a-Bromo-n-butyric acid 


97-105/10 mm. 




a-Bromo-n-valeric acid 


232 


1.048J^ 


Hexahydrobenzoic acid, m. 30° 


236 


0.914-2/ 


n-Caprylic acid, m. 16° 


268-70 


0.930f| 


Capric acid, m. 30° 


275 d. 


0.91025 


Undecenoic acid, m. 24° 



GROUP IV. SUB-GROUP 1 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


14° 


285°/ 100 mm. 


Oleic acid 


16 


236 


«-Caprylic acid 


24 


275 d. 


Undecenoic acid 


— 


168/i2mm. 


Undecanoic acid 


24 


205 


a-Bromopropionic acid 


30 


232 


Hexah3'drobenzoic acid 


30 


268-70 


Capric acid 


42 


360 


Benzoic anhydride 


43 


225/100 mm. 


Laurie acid 


48 


280 


Hydrocinnamic acid 


51 


234/15 mm. 


Elaidic acid 


53-4 


250/100 mm. 


Myristic acid 


62 


340-50 d. 


Palmitic acid 


69 


360-80 


Stearic acid 


76 


262 


Phenylacetic acid 


96 


285 d. 


Phenoxyacetic acid 


98 


250 d. 


Methyl ether salicyhc acid 


102 


259 


o-Toluic acid 


105 


272/100 mm. 


PimeUc acid 


106 


360 d. 


Nonanedicarboxylic acid (Azelaic) 


110 


263 


m-Toluic acid 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP IV. SUB-GROUP 1— Continued 



207 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


117° d. 




Benzylmalonic acid 


121 


249° 


Benzoic acid 


126 




Phenylglycine 


131 


284 


Phthalic anhydride 


132-4 


230 d. 


Pyromucic acid 


133 


295/100 mm. 


Sebacic acid 


133 


299 d. 


Cinnamic acid 


135 




Acetylsalicylic acid 


136 




Dihydroxy stearic acid 


136 




Picolinic acid 


136 




Phenylpropiolic acid 


140 




o-Chlorobenzoic acid 


140 




m-Nitrobenzoic acid 


140 




Suberic acid 


144 




Anthranilic acid 


146 




o-Nitrobenzoic acid 


148 




o-Bromobenzoic acid 


■ 148-9 




Oxanilic acid 


150 




Benzilic acid 


151 




4-Hydroxy-m-toIuic acid 


152 




Adipic acid 


152 




p-Nitrophenylacetic acid 


155 




m-Bromobenzoic acid 


157 




Salicylic acid 


158 




m-Chlorobenzoic acid 


158 




o-Aminocinnamic acid 


162 




o-Iodobenzoic acid 


162 




a-Naphthoic acid 


163 




2-Hydroxy-m-toluic acid 


163-5 




di-Benzoyl alanine 


170 d. 




dZ-a-Amino-n-caproic acid 


172-4 




Acetylphenylglycine 


174 




m-Aminobenzoic acid 


174-5 




Propyl Red 


175 




p-Aminocinnamic acid 


177 




p-Toluic acid 


179 




2, 4-Diiiitrobenzoic acid 


179 




iV-Methyl anthranilic acid 


181-2 




Methyl Red 


184 




Anisic acid 


185 




/3-Naphthoic acid 


185 




Acetylanthranilic acid 



208 QUALITATIVE ORGANIC ANALYSIS 

GROUP IV. SUB-GROUP 1— Continued 



MELTING-POINT 



186° 

187 

187 

190-200 d. 

140 d.-191 

194 

196 d. 

196 

200 

200+ subl. 

200-20 d. 

204 

206 

207 

207 

210 

213 

213-4 

216 

216 

220 d. 

220-5 d. 

220+ d. 

230 d. 

228-30 

230 

237 

237-8 d. 

238 

242 d. 

242 

245 d. 

249-50 

252 d. 

250 d. 

251 

256+ subl. 

263+ d. 

265 

274 

285 



NAME OF COMPOUND 



p-Aminobenzoic acid 

d-Camphoric acid 

Hippuric acid 

o-Phthalic acid 

3, 6-Dichlorophthalic acid 

Acetylphenylglycine 

Protocatechuic acid 

m-Nitrocinnamic acid 

m-Hydroxybenzoic acid 

Fumaric acid 

Tannic acid 

3, 5-Dinitrobcn,zoic acid 

p-Coumaric acid 

o-Coumaric acid 

Vanillic acid 

Phenyl cinchoninic acid 

p-Hydroxybenzoic acid 

p-Cyanobenzoic acid 

2-Hydroxy-3-naphthoic acid 

Piperic acid 

2, 4, 6-Trinitrobenzoic acid 

p-Hydrazinobenzoic acid 

Gallic acid 

d- and Z-Asparagine 

Nicotinic acid 

Quinolinic acid 

o-Nitrocinnamic acid 

dZ-a-Aminophenylacetic acid 

p-Nitrobenzoic acid 

Methylenedisalicylic acid 

p-Chlorobenzoic acid 

p-Hydroxyphenylglycine 

Acetyl-7w-aminobenzoic acid 

Acetyl-p-aminobenzoic acid 

Tetrachlorophthalic acid 

p-Bromobenzoic acid 

dZ-Phenylaminoacetic acid 

dZ-Phenylalanine 

p-Iodobenzoic acid 

Naphthalic acid 

p-Nitrocinnamic acid 



CLASSIFIED TABLES OF COMPOUNDS 



GROUP IV. SUB-GROUP 1— Continued 



209 



MELTING-POINT 




NAME OF COMPOUND 


300° 




IsophthaUc acid 


310 subl. 




Isonicotinic acid 


314+ d. 




Z-Tyrosine 


300+ subl. 




Terephthalic acid 


330 




a-Naphthophthalein 


subl. 




dZ-«-Amino-n-valeric acid 






di-«-Aininocaprylic acid 






, 5-AminosaIicylic acid 



GROUP IV. SUB-GROUP 2 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


175° 




o-Chlorophenol, m. 7° 


190 


1.05111 


o-Cresol, m. 31° 


194-5 




o-Bromophenol 


196 


1.165ff' 


Salicylaldehyde 


202 


1.039|f 


p-Cresol, m. 36° 


202 


1.039if 


TO-Creso] 


205 


1.1530 


Guaiacol, m. 28° 


211 


1.036" 


1, 3, 4-XylenoI, m. 26° 


214 




m-Chlorophenol, m. 28° 


224 


1.189if 


Methyl salicylate 


230 


1.1842 


Ethyl salicylate 


236 




m-Bromophenol, m. 32° 


237 


0.978f^ 


Carvacrol 


238 d. 


1.098^^5 


n-Propyl salicylate 


243 


1.070* 


Resorcinolmonomethyl ether 


250 


1.069|f 


Eugenol 


250 


1.06515 


Isoamyl salicylate 


153/10 mm. 




Resorcinol monacetate 




267 


1.090|f 


Isoeugenol 



'H£MTERN«N[VEB8m'i 




210 



QUALITATIVE ORGANIC ANALYSIS 



GROUP IV. SUB-GROUP 2 
Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


26° 


211° 


1, 3, 4-Xylenol 


28 


205 


Guaiacol 


28 


214 


7n-Chlorophenol 


31 


190 


o-Cresol 


32 


236 


7«-Bromophenol 


36 


202 


p-Cresol 


37 


217 


p-Chlorophenol 


42 


180 


Phenol 


42 


172/12 nun. 


Phenyl salicylate 


45 


214 


o-Nitrophenol 


49 


211 


1, 3, 2-Xylenol 


50 


232 


Thymol 


52-3 


236 


6-Chloro-m-cresol 


53 


243 


Hydroquinonemonomethyl ether 


60 




1, 2-Dihydroxynaphthalene 


63 


236 


p-Bromophenol 


65 


225 


1, 2, 4-Xylenol 


67 


244 


s-Trichlorophenol 


68 


219 


Hydroxymesitylene 


70 




Methyl /rt-hydro.\ybenzoate 


71 


234 


Pseudocumenol (1, 2, 4-Trimethyl- 
5-hydroxybenzene) 


72 


282 


wi-Hydroxyethylbenzoate 


74 


211 


1, 4, 2-Xylenol 


75 


266 


8-Hydroxyquinoline 


74-6 


165/30 mm. 


p-Dimethylaminophenol 


80 


285 


Vanillin 


80 d. 




o-Methylaminophenol 


81 




2-Hydroxy-l-naphthylaldehyde 


85 




p-Methylaminophenol 


85 


265-8 


7rt-Dimethylaminophenol 


93 




/«-Nitrophenol 


94 


278-80 


a-Naphthol 


96 




vS-Tribromophenol 


104 




Tw-Hydroxybenzaldehyde 


109 




a-N itroso-/3-naphthol 


110 




Bromohydroquinone 


114 




p-Nitrophenol 


114 




2, 4-Dinitrophenol 


115 




p-Hydroxybenzaldehyde 


116 


298 


p-Hydroxyethylbenzoate 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP IV. SUB-GROUP 2— Continued 



211 



MELTING-POINT 



NAME OP COMPOUND 



122° 

122 

122 

125 d. 

128-30 

131 

140 

140 

147-8 d. 

150 

150 

151 

152 

162 

165 

166 

168 

168-9 

169-70 

170 

170 

170-90 

171 

171 

173 

176 

181 

184 d. 

185 

190 

192 d. 

199 

201 

204 

210 

210-11 

213 

218 

250-3 

289 

290+ 



Picric acid 

^-Naphthol 

m-Aminophenol 

p-Nitrosophenol 

Benzeneazo-o-cresol 

p-Hydroxymethylbenzoate 

Salicylamide 

1, 8-Dihydroxy naphthalene 
/3-Nitroso-a-naphthol 
Ethyl gallate 
Protocatechuic aldehyde 
4-Hydroxy-m-toluic acid 
p-Hydroxyazoxybenzene 
p-Hydroxybenzamide 
Arbutin (Glucoside) 
N-Acetyl-p-aminophenol 

2, 4-Dinitro-6-aminophenol 
N-Acetyl-p-methylanunophenol 
Dichlorohydroquinone 
o-Aminophenol 
TO-Hydroxybenzamide 

Aurin 

Quinhydrone 

o-Azophenol 

5-Amino-2-hydroxytoluene 

1, 4-Dihydroxy naphthalene 

1, 4-Naphtholaldehyde 

p-Aminophenol 

p-BenzalaminophenoI 

1, 4-Nitrosonaphthol 

Thymolphthalein 

2-Hydroxyquinoline 

N-Acetyl-o-aminophenol 

p-Azophenol 

Tetrabromo-o-cresol 

5-Benzalamino-o-cresoI 

o-Cresolphthalein 

Phloroglucinol 

Phenolphthalein 

Alizarin 

Fluorescein 



212 



QUALITATIVE ORGANIC ANALYSIS 

GROUP IV. SUB-GROUP 3 
Solids 



MELTING-POINT 




NAME OF COMPOIND 


172° 




Phenyl ethyl barbituric acid 


188 




Diethyl barbituric acid 


200 




Isatin 


230 d. 




Nitroguanidine 


233 




Phthalimide 


d. 




Nitro urea 


270 




Theophyllin 


300 subl. 




Theobromine 






Cyanuric acid 






Uric acid 



GROUP IV. SUB-GROUP 4 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


101° 

114 

130 

226 d. 


1.14415 
1.05615 
1.022^ 
1.1602 


Nitromethane 
Nitroethane 
n-Nitropropane 
Phenylnitromethane 



GROUP IV. SUB-GROUP 4 
Solids 



MELTING-POINT 




NAME OF COMPOUND 


33-5° 




a-Benzaldoxime 


59 




Acetophenone oxime 


82 




Trinitrotoluene 


109 




a-Nitroso-/3-naphthol 


120 




d-Camphor oxime 


125 




p-Nitrosophenol 


140 




Benzophenone oxime 


144 




p-Nitrosodiphenylamine 


235 




Diacetyldioxime(Dimethylglyoxime) 


237 d. 




a-Benzildioxime 



CLASSIFIED TABLES OF COMPOUNDS 



213 



GROUP IV. SUB-GROUP 5 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 




170° 


Thiophenol 




195 


7«-Thiocresol 


15° 


194 


o-ThiocresoI 


24 


— d. 


Thiobenzoic acid 


43 


194 


p-Thiocresol 


81 


28G 


/3-Thionaphthol 


83-4 




Benzenesulfinic acid 


85 




p-Toluenesulfinic acid 


88 




Benzenesulfonyl benzylamine 


95 




Benzenesulfonyl-?«-toluidine 


101 




p-Toluenesulfonylaniline 


104 




Benzenesulfonyl-o-nitraniline 


112 




SuKanilide 


112 




Benzenesulfonylaniline 


115 




Thiobenzamide 


117 




p-Toluenesulfonyl-p-toluidine 


120 




Benzenesulfonyl-p-toluidine 


121 




Benzenesulfonyl-p-chloroaniline 


124 




Benzenesulfonyl-o-toluidine 


132 




Benzenesulfonyl-m-nitraniline 


136 




p-ToIuene sulfonamide 


139 




Benzenesulfonyl-7>nitraniline 


150 




a-Napthalenesulfonamide 


154 




o-ToIuene sulfonamide 


156 




Benzenesulfonamide 


157 




Phenylthiohydantoic acid 


164 




Thiosalicylic acid 


217 




|3-Napthalenesulfonamide 


220 d. 




o-Benzoic sulfimide (Saccharin) 


240 d. 




Thiobarbituric acid 






Z-Cystine 






Many sulfonic acids, such as sul- 
fanilic, aminonaphthalene sulfonic, 
etc. 






Sulfonephthaleins, such as phenol- 
sulfonephthalein, thymolsulfone- 
phthalein, dibromothymolsulfone- 
phthalein, o-cresolsulfonephthalien 
etc. 



214 



QUALITATIVE ORGANIC ANALYSIS 



GROUP IV. SUB-GROUP 6 
Liquids 











BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


169° 
181 


1.081^^ 

1.026-Y- 


Methyl acetoacetate 
Ethyl acetoacetate 


GROUP IV. SUB-GROUP 6 

Solids 


MELTING-POINT 


BOILING- POINT 


NAME OF COMPOUND 


60° 

80 
108-9 


262-4° 
270 


Benzoylacetone 
Dibenzoylmethane 
Dehydracetic acid 





CLASSIFIED TABLES OF COMPOUNDS 



215 



GROUP V. SUB-GROUPS 1, 2, 3 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


92 


0.804^5 


Isovaleraldehyde 


100-1 


0.814^5 


tert-Amyl alcohol 


101 


0.81215 


Methyl propyl ketone ' 


102 


0.833f 


Diethyl ketone 


103 


0.818^1 


?i-Valeraldehyde 


10) 


0.826° 


Pinacoline 


116 


1.203f 


a-Epichlorohydrin 


116-8 




Methyl n-propjl carbinol 


118 


0.823» 


sec- Ainyl alcohol 


119 


0.8031" 


Lsobutyl methyl ketone 


124 


0.994-Y- 


Paraldehyde, m. 12° 


127-8 


0.8332 


n-Hexjd aldehyde 


129-31 


0.81020 


Isoamyl alcohol 


130 


0.858-2^1 


Mesityl o.xide • 


130-1 


0.9423J- 


Cyclopentanone 


136 


0.833° 


sec-Hexyl alcohol 


136-9 




7i-Butyl methyl carbinol 


137 


O.8I720 


7i-Amyl alcohol 


139 


0.94021 


Cyclopentanol 


142 




Triethyl carbinol 


151 


0.837° 


Methyl 7i-amyl ketone 


155 


0.947-^ 


Cyclohexanone 


155-6 


0.849^ 


7i-Heptylaldehyde 


157-8 


0.82020 


7i-Hexyl alcohol 


160 


0.944 


Cyclohexanol, m. 16° 


165-70 




Methyl cyclohexanols 


175-6 


0.830i« 


7i-Heptyl alcohol 


176 


1.39616 


Glycerol a-dichlorohydrin 


179 


0.819-2^ 


sec-Octyl alcohol 


179 


l.OSO-V^- 


Benzaldehyde 


179-81 


0.969° 


Cycloheptanone 


180 




7i-Hexyl methyl carbinol 


182 


1.380° 


Glycerol /3-dichlorohydrin 


94-5/15 mm. 




Di-7i-butyl carbinol 


190-5 


0.8702° 


Z-Linalool 


192 


0.837° 


7i-0ctyl alcohol (primary) 


198 


0.885-2^^ 


Phorone, m. 28° 


199 


1.02422 


7«-Toluylaldehyde 


98-100/35 mm. 




Para 7i-butyraldehyde 



216 QUALITATIVE ORGANIC ANALYSIS 

GROUP V. SUB-GROUPS 1, 2, 3— Continued 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


200° 




0-Toluylaldehyde 


200 


1.0232 5 


Acetophenone, m. 20° 


203 


1.013 


Methyl phenyl carbinol 


205 


1.050|f 


Benzyl alcohol 


205-^ 


0.8562 


Citronellal 


207 


0.8962 


Z-Menthone 


114-8/ 15 mm. 




Tri-7i-butyl carbinol 


213-4 


1.29^ 


o-Chlorobenzaldehyde 


213-4 




7n-Chlorobenzaldehyde, m. 17° 


218 


0.93520 


Terpineol, m. 35° 


219 


1.02415 


;3-Phenylethjd alcohol 


219 


2.168" 


Glycerol-/J-dibromohydrin 


219 d. 


2.1118 


Glycerol-a-dibromohydrin 


220 d. 


1.050-2^ 


Cinnamaldehyde 


222 


1.013 


Methyl-;j-tolyl ketone 


224-8 d. 


0.897^5 


Citral 


113-4/15 mm. 


0.86120 


Rhodinol 


229 


0.88315 


Geraniol 


231 


0.8391 


n-Decyl alcohol 


235 


1.00818 


Phenylpropyl alcohol 


241-2 




o-Metho.\ybenzaldehyde 


248 


I.I2318 


Anisaldehyde, m. 0° 


143/ 15 mm. 


0.831-2^ 


Lauryl alcohol, m. 24° 


143-5/ 15 mm. 


0.904 


Pseudoionone 


250 


1.030^V- 


Cinnamyl alcohol, m. 33° 


262 




Benzalacetone, m. 41° 


174-81/10 mm. 




Dibenzyl ketone 






GROUP V. SUB-GROUPS 1, 2, 3 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


12° 


124° 


Paraldehyde 


16 


160 


Cyclohexanol 


16-8 


105-7/Hmm. 


Propiophenone 


20 


200 


Acetophenone 


24 


143/15 mm. 


Lauryl alcohol 


28 


198 


Phorone 


33 


250 


Cinnamyl alcohol 



CLASSIFIED TABLES OF COMPOUNDS 



217 



GROUP V. SUB-GROUP 1, 2, 3— Continued 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


35° 


218° 


Terpineol 


35 


243 


o-Methoxybenzaldehyde 


37 


263 


Piperonal 


39 




Myristyl alcohol 


40-1 




a, 7-Dichloroacetone 


41 


262 


Benzalacetone 


42 


212 


Z-Menthol 


45 


259 


Anisic alcohol 


47 


213 


p-Chlorobenzaldehyde 


48 


305 


Benzophenone 


50 


344 


Cetyl alcohol 


50 




w-Bromoacetophenone 


52-4 




Phenyl p-tolyl ketone 


55-6 




o-Phthaldehyde 


57 




Benzalacetophenone 


59 


244 


co-Chloroacetophenone 


60 




^-Naphthaldehyde 


68 




Toluquinone 


70-1 




2, 4-Dichlorobenzaldehyde 


76 


274 


a-Bromo-d-camphor 


77-8 




Trichloro-ter/-butyl alcohol 


78 




Butyl chloral hydrate 


80 


285 d. 


VaniUin 


91-2 




Di-p-tolyl ketone 


95 


347 


Benzil 


102 


285 


Terpin 


112 




Dibenzyhdineacetone 


112-5 subl. 




Metaldehyde 


115 




p-Hydroxybenzaldehyde 


115-20 d. 




^-Naphthoquinone 


116 




Benzoquinone 


116 


245-8 


Terephthaldehyde 


117 




Terpin hydrate 


125 




a-Naphthoquinone 


137 


343 


Benzoin 


148 




Z-Cholesterol 


162 


360 


Triphenylcarbinol 


167 




Tribromo-^ert-butyl alcohol 


171-2 subl. 




Polyoxymethylene 


173 




Xanthone 


176 


205 


d-Camphor 


177 




2-M ethyl anthraquinone 


178 




dZ-Camphor 



218 QUALITATIVE ORGANIC ANALYSIS 

GROUP V SUB-GROUPS 1, 2, S—dontinued 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


180° 




Populin (Glucoside) 


185 




Coniferin (Glucoside) 


198 




Camphorquinone 


201 




Salicin (Glucoside) 


202 


360° 


Phenanthraquinone 


204 


212 


d-Borneol 


261 




Acenaphthoquinone 


273 (280) 


380 


Anthraquinone 


290 subl. 




Chloranil (Tetrachlorobenzoquinone) 



GROUP V. SUB-GROUP 4 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


35° 


0.719-1/ 


Ethyl ether 


45 


0.872-1/ 


Methylal 


64 




Dimethylacetal 


69 


0.7242 


Diisopropyl ether 


73-4 


0.817Y 


tt-Butyraldehyde 


89 




Ethylal 


97-101 




n-Amyl methyl ether \ 


101 




Methyl orthoformate \ 


102 


0.831-2/ 


Acetal 


116 


1.13812 


a, a'-Dichloroethyl ether (s3Tn.) 


116 


1.203f 


Epichlorohydria 


124 


0.994-2/ 


Paraldehyde 


140 


0.7692" 


7i-Butyl ether 


140 


1.1742 3 


a, /3-Dichloro diethyl ether 


145 


0.896-/ 


Ethyl orthoformate 


154 


0.988-2/ 


Anisole 


157 


1.02615 


Monochloroacetal 


167 


0.981* 


Benzyl methyl ether 


170 




M onobromoacetal 


171 


0.996" 


o-Cresyl methyl ether 


172 


0.774f| 


Isoamyl ether 


172 


0.979* 


Phenetole 


174-6 


0.922 


Cineol 


175-8 




/3, /3'-Dichloroothyl other 


176 


0.987" 


p-Cresyl methyl ether 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP V. SUB-GROUP 4:— Continued 



219 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


177° 


0.985* 


m-Cresyl methyl ether 


185 




Benzyl ethyl ether 


187-90 




n-Amyl ether 


195 




o-Chloroanisole 


200 




p-Chloroanisole 


206 


1.086^5 


Veratrole (1, 2-Dimethyoxy benzene) 
m. 15° 


208 




o-Chlorophenetole 


210 


0.950 


n-Butyl phenyl ether 


212 




p-Chlorophenetole, m. 20° 


212 




Benzyl isobutyl ether 


213-6 




Benzyl n-butyl ether 


214 


l.OSOf 


Resorcinyl dimethyl ether 


216 


0.954" 


Thymyl methyl ether 


218 




o-Bromoanisole 


223 


0.944° 


n-Butyl o-cresyl ether 


223 


1.494» 


p-Bromoanisole 


224 




o-Bromophenetole 


229 




p-Bromophenetole 


232 


1.09618 


Safrole 


232 


0.98928 


Anethole, m.21° 


244 


1.055^5 


Eugenol methyl ether 


246 


1.1251* 


Isosafrole 


252 


1.07320 


Diphenyl ether, m. 28° 


265 


1.096^* 


a-Naphthyl methyl ether 


278 


1.074 


a-Naphthyl ethyl ether 


282 




/3-Naphthyl ethyl ether, m. 37° 


178-9/11 mm. 




/3-Naphthyl isoamyl ether, m. 26° 


298 


1.0361 « 


Dibenzyl ether 



220 



QUALITATIVE ORGANIC ANALYSIS 



GROUP V. SUB-GROUP 4 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


15° 


207° 


Veratrole 


20 


212 


p-ChlorophenetoIe 


21 


232 


Anethole 


26 


325 


/3-Naphthyl isoamyl ether 


28 


252 


Diphenyl ether 


32 


300 


Apiole 


37 


282 


/3-Naphthyl ethyl ether 


43 


246 


s-Trichlorophenetole 


55 


212 


Hydroquinone dimethyl ether 


60 


240 


s-Trichloroanisole 


72 


274 


/3-Naphthyl methyl ether 


72 




s-Tribromophenetole 


87 




s-Tribromoanisole 



GROUP V. SUB-GROUP 5 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


72-5° 


1.21811 


Methyl chlorocarbonate 


77 


0.924f 


Ethyl acetate 


90 


1.06922 


Methyl carbonate, m. 0° 


92 


O.Ollf 


Methyl isobutyrate 


93 


1.14415 


Ethyl chlorocarbonate 


98 




Isobutj^l formate 


98 


0.914" 


Ethyl propionate 


101 


0.899-1/ 


n-Propyl acetate 


102 


0.919f 


Methyl n-butyrate 


103 


0.938 


Allyl acetate 


107 


0.911« 


n-Butyl formate 


110 


0.890f 


Ethyl isobutyrate 


111 


0.892 


sec-Butyl acetate 


113 




n-Propyl chlorocarbonate 


116 


0.892f 


Isobutyl acetate 


116 


O.OOOf 


Methyl isovalerate 


120 


0.899f 


Ethyl n-butyrate 


122 


0.902^ 


n-Propyl propionate 


123 


0.894^ 


Isoamyl formate 


125 


0.8822 


n-Butyl acetate 


126 


O.976-24P- 


Ethyl carbonate 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP V. SUB-GROUP 5— Continued 



221 



BOILING-POINT 


SPECIFIC GRAVITY 


NAMR OF COMPOUND 


127-30° 


0.9100 


Methyl n-valerate 


128 


0.879° 


Isopropyl n-butyrate 


130 


1 . 23.5f^ 


Methyl chloroacetate 


134 


0.885f 


Ethyl isovalerate 


137 


0.892f 


Isobutyl propionate 


140-5 




n-Butyl chlorocarbonate 


142 


0.876-1/ 


Isoamyl acetate 


143 


0.893" 


n-Propyl n-butyrate 


144 d. 




Methyl bromoacetate 


145 


0.87620 


Ethyl n-valerate 


145 


1 . 158-2/ 


Ethyl chloroacetate 


145 


1.178 


/3-Chloroethyl acetate 


145 


'0.84713 


Ethyl orthoformate 


146 


1.087^ 


Ethyl a-chloropropionate 


147 


0.875f 


Isobutyl isobutyrate 


150-2 


1.03120 


Ethyl lactate 


157 


0.888f 


Isobutyl n-butyrate 


158 


1.2822/ 


Ethyl dichloroacetate 


159 


1.507|f 


Ethyl bromoacetate 


160 


0.888f 


Isoamyl propionate 


162 


1.39320 


Ethyl a-bromopropionate 


164-6 




n-Propyl carbonate 


165 


0.888 


n-Butyl n-butyrate 


167 




a-Angelica lactone, m. 18-19° 


167 


1.38320 


Ethyl trichloroacetate, m. 141° 


167 


0.87320 


Ethyl n-caproate 


170 


1.073|f 


Methyl acetoacetate 


171-6 




Cyclohexylacetate 


174-6 




Methyl n-heptylate 


177 


1.020»o 


Methyl methylacetoacetate 


178 


1.1071'^ 


Methyl methylmalonate 


178 


0.8820 


Isoamyl butyrate 


180 


1.08115 


n-Butyl chloroacetate 


181 


1.0242^0 


Ethyl acetoacetate 


181 


1.16015 


Methyl malonate 


83-5/20 mm. 




o-Cresyl acetate 


186 


1.07611 


Ethyl oxalate 


186 


1 . 1280 


Ethyleneglycoldiacetate 


187 


1.0098 


Ethyl methylacetoacetate 


190 


0.9951* 


Methyl ethylacetoacetate 


67-70/8 mm. 




Ethyl n-heptylate 


191 




Methyl levulinate 


193 


0.88718 


Methyl caprylate 



222 



QUALITATIVE ORGANIC ANALYSIS 
GROUP V. SUB-GROUP b— Continued 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


194° 


0.870" 


Isoamyl isovalerate 


196 


1.02115 


Ethyl methylmalonate 


196 


1.093f 


Phenyl acetate 


198 


1.05411 


Ethyl malonate 


198 


1.0^4-1/ 


Methyl benzoate 


198 


0.998^2 


Ethyl ethylacetoacetate 


90-1°/ 14 mm. 




Isopropyl oxalate 


202 


1.01620 


Ethyl levulinate 


205 


0.9242 


Butyl carbonate 


100-5/15 mm. 


0.89520 


Linalyl acetate 


108-10/ 10 mm. 




Ethyl n-butylmalonate 


206 (215-6) 


1.05716-5 


Benzyl acetate 


207 


1.00511 


Ethyl ethylmalonate 


207 


0.8870 


Ethyl caprylate 


210 


0.885 


sec-Octyl acetate 


211 




Phenyl propionate, m. 20° 


213 


1.0380 


n-Propyl oxalate 


213 


1 -05411 


Ethyl benzoate 


217 


1.04415 


Ethyl succinate 


218 


1. 01711 


Isopropyl benzoate 


220 


1.0441 « 


Methyl phenylacetate 


221 




Bornyl acetate, in. 29° 


223 




Methyl caprate 


110-12/ 10 mm. 




Ethyl caprate 


226 


1.04611 


Ethyl phenylacetate 


227 


0.985-2^ 


/-Menthyl acetate 


129-30/8 mm. 




Ethyl di-n-butylmalonate 


228 




Methyl o-methoxybenzoate 


128-32/i8n]m. 




n-Butyl phenylacetate 


128-30/20 mm. 




Isobutyl phenylacetate 


133-4/20 mm. 




Ethyl glutarate 


230 


1.03216 


7i-Propyl benzoate 


230 


1.058if 


Allyl benzoate 


230 




Ethyl diethylmalonate 


127-9/8 mm. 




Methyl laurate 


233-5 


1.42615 


Ethyl bromomalonate 


131-2/15 mm. 




Ethyl adipate 


235 




|3, /3'-Dichloroethyl carbonate 


235-7 


1.137if 


Ethyl salicylate 


238 


1.0331 6 


Benzyl n-butyrate 


241 


1.00311 


Isobutyl benzoate 


243 


1.0100 


n-Butyl oxalate 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP V. SUB-GROUP 5— Continued 



223 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


245° 


1.009" 


Thymyl acetate 


245 


1.1501^ 


Methyl pheno.xyacetate 


154-5/15 mm. 




n-Butyl salicylate 


246 


1.016* 


n-Propyl succinate 


249 


1.0002 


n-Butyl benzoate 


251 


1.10417 


Ethyl phenoxyacetate 


260 


1.159|f 


Triacetin 


262 


1.004" 


Isoamyl benzoate 


262 


0.96811 


Isoamyl oxalate 


263 


1.042-%«- 


Methyl cinnamate, ra. 36° 


265 


0.97415 


Isobutyl succinate 


265-70 




7, 7'-Dichloropropyl carbonate 


269 


0.8671" 


Ethyl laurate 


269-70 


1.119* 


Ethyl anisate, m. 7° 


185-6/50 mm. 




rt-Butyl o-methoxybenzoate 


270 


1 -04511 


Isoamyl salicylate 


270 




Methyl aconitate 


271 


1.0502 


Ethyl cinnamate, m. 12° 


196-8/15 mm. 




/i-Butyl tartarate 


275 


1.130^0 


Isopropyl tartarate 


275 


1.0741* 


Ethyl aconitate 


278 d. 




Resorcinol diacetate 


280 


1.2062 


Ethyl tartarate 


282 


1 . 189ff 


Methyl phthalate 


283 


1.034i« 


Ethyl benzylacetoacetate 


285 


1.03220 


Glycerol tributyrate 


288 




Methyl sebacate, m. 38° 


208/26 mm. 




Benzyl salicylate 


294 


1 . 137-2/ 


Triethyl citrate 


295 


1.118-2/- 


Ethyl phthalate 


152-5/io mm. 




Isopropyl phthalate 


297 


0.96113 


Isoamyl succinate 


300 


1.07715 


Ethyl benzylmalonate 


307 




o-Cresyl benzoate 


307 


0.9651 « 


Ethyl sebacate 


323 


I.II418 


Benzyl benzoate 


204/5 2mm. 




Tributyrin 


243-6/18 mm. 


1.093^ 


Ethyl dibenzylmalonate 


d. 




Trioleine 



224 



QUALITATIVE ORGANIC ANALYSIS' 



GROUP V. SUB-GROUP 5 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


10-15° 




Dioleine 


12 


271° 


Ethyl cinnamate 


13 


250/40 mm. 


Ethyl dibenzylmalonate 


14 




Cinnamyl cinnamate 


15-20 




Monoleine 


16-17 




Methyl myristate 


20 


211 


Phenyl propionate 


27-8 




Methyl palmitate 


29 


221 


Bornyl acetate 


30 




Benzyl cinnamate 


33 




Thymyl benzoate 


36 


263 


Methyl cinnamate 


37 


254 


Ethyl mandelate 


37-8 




Methyl stearate 


42 




Benzyl succinate 


42 




Benzyl phthalate 


45 


255 


Methyl anisate 


49-50 


245/11 mm. 


Triphenylphosphate 


52 




Methyl mandelate 


^ 54 




Trimyristin 


'' 54 




Z-Menthyl benzoate 


^55 




m-Cresyl benzoate 


■? 60 




Guaiacol benzoate 


'', 61 




Monostearine 


'', 61 




Dipalmitine 


63 




Monopalmitine 


65 


233-7 


Tripalmitine 


66 


290 


Ethyl trichlorolactate 


67 




Coumarin 


68-9 




Phenyl benzoate 


70 




Phenyl phthalate 


71 




Tristearine 


71 


205-7/15 mm. 


p-Cresyl benzoate 


72 




Phenyl cinnamate 


73 


290 


Glycol dibenzoate 


73 




PhthaUde 


76 


301 


Distearine 


78 


284 


Diphenyl carbonate 


78-9 




Methyl citrate 


80 




Benzyl oxalate 


83 




Guaiacol carbonate 


86 




Diglycolide 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP V. SUB-GROUP 5— Continued 



225 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


93'' 




^-Naphthyl salicylate 


107 




/3-Naphthyl benzoate 


123 




Hydroquinone diacetate 


127 


255° 


Lactide 


161 




Pyrogallol triacetate 


170 




Santonin 


223 




Polyglycolide 



GROUP V. SUB-GROUP 6 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


100° 


1.028-2/ 


n-Butyryl chloride 


115 


0.989-2/ • 


Isovaleryl chloride 


191 


0.978^^ 


7i-Butyric anhydride 


197 


1.212-^ 


Benzoyl chloride 


102/17 mm. 


1 . 168^ 


Phenyl acetyl chloride 


213 


1.2422 5 


Citraconic anhydride 


218 


1.570^5 


Benzoyl bromide 


145/i4 mm. 




Anisyl chloride, m. 26° 


254 




o-Methoxybenzoyl chloride 


276 


1.409-2^" 


Phthalyl chloride, m. 14° 



GROUP V. SUB-GROUP 6 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


26° 


145°/ 14 mm. 


Anisyl chloride 


35-6 


154/25 mm. 


Cinnamoyl chloride 


42 


360 


Benzoic anhydride 


63 


202 


Maleic anhydride 


85 




Diphenylcarbamide chloride 


103 




Benzoyl peroxide 


120 


260 


Succinic anhydride 


130 




Cinnamic anhydride 


131 


284 


Phthalic anhydride 


220 


270 


d-Camphoric anhydride 


274 




Naphthoic anhydride 



226 



QUALITATIVE ORGANIC ANALYSIS 

GROUP V. SUB-GROUP 7 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OP COMPOUND 


21° 




3-M ethy Ibutene- 1 


22-37 


0.66ff 


Amylene (techn.) 


35-8 


0.678" 


Isoamylene 


42 


0.805-L9 


Cyclopentadiene 


58-9 


0.690-2/ 


Diallyl 


102-4 




2-Methyl cyclohexene 


102-4 




3-Methyl cyclohexene 


107-9 




4-M ethyl cyclohexene 


146 


0.925 


Styrene 


155-60 


0.85820 


Pinene 


160-70 


0.8602 5 


Terebene 


167 


0.814-2/ 


Menthene 


176 


0.846i» 


Limonene 


176 


0.851i« 


Sylvestrene 


176-7 


0.914if 


Allyl benzene 


180 


1.04015 


Indene 


181 


0.85416 


Dipentene 


212 




Dihydronaphthalene 


232 




Safrole 


244 


1.035|i 


Eugenyl methyl ether 


246-8 




Isosafrole 



GROUP V. SUB-GROUP 7 
Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


15° 
51 

125 


212° 

160 
306 


Dihydronaphthalene 

i-Camphene 

Stilbene 



CLASSIFIED TABLES OF COMPOUNDS 



227 



GROUP VI. SUB-GROUPS 1 and 2 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


30-1° 


0.613V^ 


Isopentane 


30-50 


0. 62-. 6325 


Petroleum ether (mixture) 


36 


0.645" 


Pentane 


50-70 


0. 63-. 6625 


Benzine (ligroin mixture) 


68 


0.660-V- 


n-Hexane 


70-100+ 


0. 70-. 7525 


f Gasoline (mixture) 
I Ligroin (mixture) 


80 


0.874-2/ 


Benzene, m. 5° 


80 


0.790-2/ 


Cyclohexane, m. 4° 


100 


0.769-2/ 


Methj^l cyclohexane 


111 


0.881| 


Toluene 


125 


0.719f 


n-Octane 


135 


0.876-V- 


Ethyl benzene 


137 


0.866 V- 


p-Xylene, m. 15° 


139 


0.871 J/ 


w-Xj'lene 


142 


0.890A 


o-Xylene 


150-300 


0. 78-. 822 5 


Kerosene (mixture) 


153 


0.875| 


Cumene (Isopropyl benzene) 


156-8 


0.735-1/ 


Diisoamyl (decane) 


158 


0.870-V- 


Propyl benzene 


164 


0.869J/ 


Mesitylene 


167-9 


0.796^5 


p-Menthane 


168 


0.889* 


Pseudocumene 


175 


0.85225 


p-Cymene 


180 


1.040^5 


Indene 


182 


0.860\"- 


Diethyl benzene (0, to, and p) 


240 


1.00119 


a-Methyl naphthalene 


242 




/3-Methyl naphthalene, m. 32° 


261 


1.0012/ 


Diphenylmethane, m. 26° 



228 



QUALITATIVE ORGANIC ANALYSIS 

GROUP VI. SUB-GROUPS 1 and 2 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


15° 


137° 


p-Xylene 


26-7 


261 


Diphenylmethane 


32 


242 


/3-M ethyl naphthalene 


52 


284 


Dibenzyl 


70 


254 


Diphenyl 


80 


218 


Naphthalene 


92 


359 


Triphenylmethane 


95 (103) 


277 


Acenaphthene 


100 


340 


Phenanthrene 


115 


295 


Fluorene 


125 


306 


Stilbene 


213 


360 


Anthracene 



GROUP VI. SUB-GROUPS 3 and 4 

Liquids 



BOILING-POINT 


specific GRAVITY 


NAME OF COMPOUND 


12-3° 


0.9210 


Ethyl chloride 


36 


0.8592 


Isopropyl chloride 


38 


1.450^5 


Ethyl bromide 


42 


1.378f 


Methylene chloride 


43 


2.285^5 


Methyl iodide 


46 


0.89220 


n-Propyl chloride 


46 


0.9550 


Allyl chloride 


51 


0.84715 


tert-Butyl chloride 


55 




Acetylene dichloride 


60 


1.1802 2 


Ethylidene chloride 


60 


1.31020 


Isopropyl bromide 


61 


1 . 504 1 2 


Chloroform 


68 


0.88015 


Isobutyl chloride 


70 




2, 2-Dichloropropane 


70 


1.43615 


Allyl bromide 


71 


1.35220 


« -Propyl bromide 


72 


1.20215 


lert-Buty\ bromide 


72 


1 .94311 


Ethyl iodide 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP VI. SUB-GROUPS 3 and 4^Continued 



229 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


74° 


1.325-2/ 


1, 1, 1-TrichIoroethane 




77 


0.88720 


?i-Butyl chloride 




78 


1.591|f 


Carbon tetrachloride 




83 


1.667i« 


1-Chloro-l-bromoethane 




83 


1.2562 


Ethylene chloride 




86 


0.8701" 


tert-Amyl chloride 




88 




Trichloroethylene 




89 


1.703Y 


Isopropyl iodide 




91 


1.27215 


Isobutyl bromide 




98 


2.498^5 


Methylene bromide 




98 d. 


1.571" 


tert-Buty] iodide 




98 


1.1661* 


Propylene chloride 




100 


1.27920 


M-Butyl bromide 




100 


0.886*^ 


Isoamyl chloride 




101 


1.84812 


Allyl iodide 




102 


1.743-2^0 


7i-Propyl iodide 




107 


1.6891 » 


s-Ethylene chlorobromide 




108 


1.194|f 


tert-Amyl bromide 




112 


2.1001^ 


Ethylidene bromide 




114 


I.4571" 


1, 2, 2-Trichloroethane 




118 


1.2062 2 


Isoamyl bromide 




119 


1.59520 


sec-Butyl iodide 




120 


1.60819 


Isobutyl iodide 




121 


1.631^ 


Tetrachloroethylene 




125 


1.1891/ 


Trimethylene chloride 




128 


1.49719 


tert-Amyl iodide 




130 


2.178^ 


Ethylene bromide, m. 9° 




130 


I.6I320 


n-Butyl iodide 




132 


iii2ii_ 


. Chlorobenzene 
Chlorocyclohexane 




141-2 


0.9815 




142 


1.93320 


Propylene bromide 


^ 


147 


I.6I40 


s-Tetrachloroethane 




148 


1.47320 


Isoamyl iodide 




151 


2.90415 


Bromoform, m. 9° 




155 


1.41715 


Glycerol trichlorhydrin 




157 


1.49120 


Bromobenzene 




159 


1.081-2/ 


o-Chlorotoluene 




161 


1.693i/ 


Pentachloroethane 




162 


1.072-2/ 


TO-Chlorotoluene 




162 


1.0702 


p-Chloro toluene, m. 7° 




165 


1.820-2/ 


1, 2-Dibromobutane 




165 


1.9731^ 


Trimethylene bromide 





230 QUALITATIVE ORGANIC ANALYSIS 

GROUP VI. SUB-GROUPS 3 and A— Continued 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


eOVlOmm. 




Bromocyclohexane 


172 


1.307« 


TO-Dichlorobenzene 


174-8 


1.133^8 


n-Heptylbromide 


179 


1.114* 


Benzyl chloride 


179 


1.328<' 


o-Dichlorobenzene 


180 d. 


3.285^5 


Methylene iodide, m. 4° 


181 


1.422-2/ 


o-Bromotoluene 


183 


1.410^ 


m-BromotoIuene 


185 


1.354\4- 


p-Bromotoluene, m. 28° 


188 


1.83220 


lodobenzene 


195 


1.2462 


2, 4-Dichlorotoluene 


198 


1.438-V- 


Benzyl bromide 


200 d. 


2.971Y 


s-Tetrabromoethane 


204 


1.6982 


m-Iodotoluene 


211 


1.69720 


o-Iodotoluene 


211 




p-Iodotoluene 


212 


1.295i« 


Benzal chloride 


213 


1.380^* 


Benzotrichloride 


214 




o-Chlorobenzyl chloride 




214 




p-Chlorobenzyl chloride, m. 29° 




110-15/15 mm. 




o-Bromobenzyl chloride 




219 


1.955Y 


m-Dibromobenzene 


219 


2.4362 3 


Glycerol tribromohydrin, m. 16° 


220 d. 


1.3925 


co-Bromostyrene 


224 


I.9771' 


o-Dibromobenzene 


175-80/45 mm. 




Lauryl bromide 


263 


1.1942/ 


a-Chloronaphthalene 


279 


1.4881' 


<x-Bromonaphthalene, m. 4° 


200/30 mm. 




Diphenyldichloromethane 



CLASSIFIED TABLES OF COMPOUNDS 



231 



GROUP VI. SUB-GROUPS 3 and 4 
Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


16° 


219° 


Glycerol tribromohydrin 


28 


185 


p-Bromotoluene 


35 


211 


p-Iodo toluene 


45 


184/20 mm. 


Diphenylbromomethane 


48 




p-Chlorobenzyl bromide 


51 


236 


p-Bromobenzyl chloride 


53 


172 


p-Dichlorobenzene 


56 


266 


/3-Chloronaphthalene 


59 


281 


/3-Bromonaphthalene 


67 




1, 2-DibromonaphthaIene 


81-2 




Ethylene iodide 


89 


219 


p-Dibromobenzene 


92 


189 d. 


Carbon tetrabromide 


106-9 




Triphenylchloromethane 


116 




Iodoform 


128 




p-Diiodobenzene 


129 


210 


Pinene hydrochloride 


157 




Bornyl chloride 


169-70 




s-Tetramethyl dibromoethane 


180 




1, 2, 4, 5-Tetrabromobenzene 


182 




Naphthalene tetrachloride 


187 




Hexachloroethane 


229 


326 


Hexachlorobenzene 



232 



QUALITATIVE ORGANIC ANALYSIS 

GROUP VII. SUB-GROUP 1 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


113° 


1.692 


Chloropicrin 


126 


1.650-1/ 


Tetranitromethane, m. 13° 


110/40 mm. 


1.02520 


1-Nitro-l-methylcyclohexane 


101-2/10 mm. 




2-Nitro-p-xylene 


209 


1.203-Y- 


Nitrobenzene, m. 5° 


224 


1.16811 


o-Nitrotoluene 


231 


1.1682 2 


m-Nitrotoluene, m. 16° 


238 


1.126^' 


4-Nitro-m-.\ylene, m. 2° 


126-8/10 mm. 




2-Nitrocymene 


150-1/iOmm. 




Methyl-o-nitrobenzoate 


265 


1.2682 


o-Nitroanisole, m. 9° 


268 




o-Nitrophenetole 


275-8 d. 




m-Nitrobenzoyl chloride, m. 35° 


I75-8O/3 ram. 




rra-Nitrobenzyl alcohol, m. 27° 



GROUP VII. SUB-GROUP 1 

Solids 



MELTING-POINT 


BOILING POINT 


NAME OF COMPOUND 


- 13* 


126° 


Tetranitromethane 


16 


231 


TO-Nitrotoluene 


27 


I75-8O/3 mm. 


TO-Nitrobenzyl alcohol 


32 


246 


o-Chloronitrobenzene 


33-5 


275-8 d. 


w-Nitrobenzoyl chloride 


43 


261 


o-Bromonitrobenzene 


44 


235 


w-Chloronitrobenzene 


44 


150/20 mm. 


o-Nitrobenzaldehyde 


44 


225 


Nitromesitylene 


45 


173/30 mm. 


7tt-Nitrobenzyl chloride 


47 


296 


Ethyl m-nitrobenzoate 


48 




o-Nitrobenzyl chloride 


49 




o-Nitroiodobenzene 


50 


315 d. 


Chloro-2, 4-dinitrobenzene 


54 


258 


p-Nitroanisole 


54 


238 


p-Nitrotoluene 


54 


266 


2, 5-Dichloronitrobenzene 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP VII. SUB-GROUP 1— Continued 



233 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


56° 


256° 


OT-Bromonitrobenzene 


58 




?rt-Nitrobenzaldehyde 


60 


304 


a-Nitronaphthalene 


60 


283 


p-Nitrophenetole 


64 




s-Trinitroanisole 


65 




TO-Nitroethylaniline 


65 




m-Nitrobenzal chloride 


66 




2, 6-Dinitrotoluene 


70 




2, 4-Dinitrotoluene 


71 




p-Nitrobenzyl chloride 


72 




Bromo- 2, 4-dinitrobenzene 


74 




o-Nitrobenzyl alcohol 


75 


202/100 mm. 


p-Nitrobenzoyl chloride 


~78' 




s-Trinitrophenetole 


78 




Methyl ?rt-nitrobenzoate 


78 




/3-Nitronaphthalene 


80 




l-Nitro-l-methylcyclohexane 


>82 




s-Trinitrotoluene 


83 


242 


p-Chloronitrobenzene 


83 




Picryl chloride 


90 


302 


TO-Dinitrobenzene 


92 




o-NitroacetanUide 


92 




3, 5-Dinitrotoluene 


93 




p-Nitrobenzyl alcohol 


93 




4, 6-Dinitro-m-xylene 


94 




3-Ni tro-4-acetaminotoluene 


96 




Methyl />nitrobenzoate 


96 




Dinitrohydroquinone diacetate 


99 




p-Nitrobenzyl bromide 


106 




p-Nitrobenzaldehyde 


116 




3-Nitro-4-aminotoluene 


116 




p-Nitrophenylacetonitrile 


118 




p-Nitroethylacetanilide 


119 




2, 4, 6-Trinitrobenzaldehyde 


121 




s-Trinitrobenzene 


126 


255 


p-Bromonitrobenzene 


130-2 




4-Nitrodiphenylamine 


142 




wi-Nitrobenzamide 


149-51 




p-Nitromethylaniline 


153 




m-Nitrobenzanilide 


153 




p-Nitromethylacetanilide 



234 



QUALITATIVE ORGANIC ANALYSIS 
GROUP VII. SUB-GROUP 1— Continued 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


154° 




m-Nitroacetanilide 


171 




p-Nitroiodobenzene 


176 




o-Nitrobenzamide 


183 




2, 6-Dichloro-4-nitroaniline 


183 




3, 5-Dinitrobenzamide 


201 




p-Nitrobenzamide 


207 




p-Nitroacetanilide 


210 




1, 5-Dinitronaphthalene 


240-7 




Nitroguanidine 



GROUP VII. SUB-GROUP 2 

Solids 



MELTING-POINT 


BOILING-POIxNT 


NAME OF COMPOUND 




273-57718 mm. 


Acetyl n-butylaniline 


38° 


298 


A^-Ethyl phenacetin 


41 


295-300 


A^-M ethyl phenacetin 


46 


284 


Formanilide 


48 


360 d. 


Benzoyl piperidine 


50 


266 


Acetyl n-propylaniline 


51 


237 d. 


A^-Phenyl urethane 


53-4 




n-Butyl carbamate 


54 


300 


Benzalaniline 


54 


258 


A'^-Ethyl acetanilide 


54 


310 


Diphenylamine 


54-6 




Acetyl methyl-o-toluidine 


60 




Isoamyl carbonate 


60 




Ethyl hippurate 


62 




A-Phenyl-a-naphthylamine 


62-4 




Isoamyl carbamate 


65 


303 


Acetyl m-toluidine 


66 




Ethyl oxanilate 


70 




Ethyl-|3-naphthyl carbamate 


71 




o-Nitroaniline 


72 




Diphenyl urethane 


73 




Formyl diphenylamine 


77 


262 


s-Trichloroaniline 


79 




Ethyl a-naphthyl carbamate 


79 


330 


Di-p-tolylamine 



CLASSIFIED TABLES OF COMPOUNDS 235 

GROUP VII. SUB-GROUP 2— Continued 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


79° 




Diethylcarbanilide 


83 


283° 


Acetyl methyl-p-toluidine 


85 




Acetoacetanilide 


86 


220 d. 


Benzyl carbamate 


88 




?i-Butyl oxamate 


90 




n-Butyranilide 


92 




o-Nitroacetanilide 


94 




3-Nitro-4-acetylaminotoluene 


97-8 




Diacetyl-iV-methyl-p-aminophenol 


98 


234 


Dichloroacetamide 


101 




Acetyl diphenylamine 


102 


260 


Methyl acetanilide 


103 




Propionanilide 


^109 




Isovaleranilide 


110 




Hydrobenzamide 


110-11 


296 


Acetyl o-toluidine 


. 114 


305 


Acetanilide 


114 




Ethyl oxamate 


116 




Diethyl bromoacetyl carbamide 


116 




3-Nitro-4-aminotoluene 


117 




3-Bromo-4-acetylaminotoluene 


117 




a-Phenylacetanilide 


117 


250 d. 


Furfuramide 


118 




p-Nitro-A'^-ethylacetanilide 


119 , 


300 


s-Tribromoaniline 


T20 


350 


Dimethylcarbanilide 


127 


347 


Triphenylamine 


127 




Acetyl p-anisidine 


128 




s-Acetyl phenylhydrazine 


128 


290 


Benzamide 


128-30 




Piperine 


129 




4-Acetamino-m-xylene 


132 




Aceto-/3-naphthylamine 


135 




Phenacetiu 


138 




2, 6-Dinitroaniline 


142 




m-Nitrobenzamide 


142 




Cinnamamide 


142 




Benzo-o-toluidine 


145 




a-Bromo-isovaleryl urea 


147 




Benzyl carbamide 


147 




Phenyl carbamide 


150 




Cinnamanihde 



236 QUALITATIVE ORGANIC ANALYSIS 

GROUP VII. SUB-GROUP 2— Continued 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


151° 




Succinanil 


153 


307° 


Acetyl-p-toluidine 


153 




m-Nitrobenzanilide 


154 




m-Nitroacetanilide 


154 


281-4 d. 


a-Phenylacetamide 


155 




o-Bromobenzamide 


155 




?n-Bromobenzainide 


158 


232 


p-Benzot oluidide 


159 




Aceto-a-naphthylamine 


159-60 




p-Toluamide 


160 




Benzanilide 


161 




Benzoyl-a-naphthylamine 


166 




Phenyl isocyanate 


167 




p-BromoacetaniUde 


167 




Dibenzylcarbamide 


168 




Benzoyl phenylhj'drazine 


168-9 




p-Acetylaminophenol 


173^ 




p-Phenetyl urea 


176 




o-Nitrobenzamide 


179 




;>Chloroacetanilide 


180 




2, 4-DinitroaniIine 


181-2 




p-Iodoacet anilide 


183 




3, 5-Dimtrobenzamide 


183 




o-Iodobenzamide 


185 




Diacetyl-o-phenylenediamine 


186 




r«-Iodobenzamide 


188 




Picramide 


189 




p-Bromobenzamide 


190 




Biuret 


191 




Diacetyl-m-phenylenediamine 


201 




p-Nit robenzamide 


203-5 




Phthalanil 


207 




p-Nitroacetanilide 


217 




p-Iodobenzamide 


219 d. 




Phthalamide 


226 




Suooinanilide 


238 


260 subl. 


Carbanilide 


238-40 




A'^-Acetyl-p-methylaminophenol 


242-3 




Succinamide 


245-7 




Oxanilide 


300+ 




Diacetyl-p-phenylenediamine 


subl. 




Oxamide 



CLASSIFIED TABLES OF COMPOUNDS 



237 



GROUP VII. SUB-GROUP 3 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


107-8^ 




Isobutyronitrile 


118 


0.79512 


7i-Butyronitrile 


141 


0.816" 


n-Valeronitrile 


155 


0.8062 


Isocapronitrile 


170 d. 


1.124 


Mandelonitrile 


191 


1.0002 5 


Benzonitrile 


205 


0.99815 


o-Toluonitrile 


207 


1.066 


Ethyl cyanoacetate 


212 


0.98414 


7w-Toluonitrile 


233 


1.017-V^ 


Phenj^l aoetonitrile 


254 


1.037" 


Cinnamonitrile 


286 


0.99515 


Trimethylene cyanide 




GROUP VII. SUB-GROUP 3 




Soli 


DS 


MELTING POINT 


BOILING-POINT 


NAME OF COMPOUND 


35° 


299° 


a-Naphthonitrile 


38 


217 


p-Toluonitrile 


52 


265-7 d. 


Succinonitrile 


66 


306 


/3-NaphthonitriIe 


129 




Methyleneamine acetonitrile 



GROUP VII. SUB-GROUP 4 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


17° 


0.90015 


Ethyl nitrite 


44 


0.93520 


n-Propyl nitrite 


65 


1.21715 


Methyl nitrate 


67 


0.888* 


Isobutyl nitrite 


75 


0.9110 


n-Butyl nitrite 


87 


1.11615 


Ethyl nitrate 


99 


0.88015 


Isoamyl nitrite 


110 


1.06315 


n-Propyl nitrate 


123 


1.02115 


Isobutyl nitrate 


130-1 


0.967-V- 


Pyrrol 


136 


1.0480 


«-Butyl nitrate 


147 


1.000^ 


Isoamyl nitrate 


166 


0.97715 


Phenyl isocyanate 


230 d. 




Camphorphenylhydrazone 



238 



QUALITATIVE ORGANIC ANALYSIS 

GROUP VII. SUB-GROUP 4 

Solids 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


36° 




Azoxy benzene 


42 


165°/ 90 mm. 


Acetone phenylhydrazone 


55 




o-Azotoluene 


59 




o-Azoxytoluene 


63 




Acetaldehyde phenylhydrazine 


66 




Diphenyl nitrosoamine 


68 




Nitrosobenzene 


68 


296 


Azobenzene 


70 




p-Azoxytoluene 


93 




Benzalazine 


96 




Diazoaminobenzene 


103-5 




Acetophenone phenylhydrazone 


127 


287/205 mm. 


l-Phenyl-3-methyl pyrazolon-5 


130 




Hydrazobenzene 


131 




o-Azophenetole 


137 




Benzophenone phenylhydrazone 


144 




p-Nitrosodiphenylamine 


144 




p-Azotoluene 


154 




pp'-Dichloroazoxybenzene 


156 




Benzaldehyde phenylhydrazone 


160 




p-Azophenetole 


161 




o-Hydrazotoluene 



GROUP VII. SUB-GROUPS 5 and 6 
Liquids 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


36° 


0.839-2/ 


Ethyl mercaptan 


37 


0.84521 


Methyl sulfide 


46 


1.292° 


Carbon disulfide 


83-4 


1.06ff 


Thiophene 


92-3 


0.837-242. 


Ethyl sulfide 


97 


0.858" 


n-Butyl mercaptan 


121 


1.046-^/ 


Methyl sulfite 


133 


1.0692* 


Methyl thiocyanate 


140 


0.887^ 


Allyl sulfide 


143 


1.00724 


Ethyl thiocyanate 



CLASSIFIED TABLES OF COMPOUNDS 
GROUP VII. SUB-GROUPS 5 and &— Continued 



239 



BOILING-POINT 


SPECIFIC GRAVITY 


NAME OF COMPOUND 


150° 


1.0062* 


Allyl isothiocyanate 


153 


0.993-2^ 


Ethyl disulfide 


161 


1.1060 


Ethyl sulfite 


184-7 


0.852 


n-Butyl sulfide 


188 


1.33315 


Dimethyl sulfate 


194 


1.0582 


Benzyl mercaptan 


208 


1.18419 


Diethyl sulfate 


221 


1.12923 


Phenyl isothiocyanate 


231 


1.15517 


Phenyl thiocyanate 


251 d. 


1 -38411 


Benzenesulfonyl chloride, m. 14° 


d. 




o-Toluenesulfonyl chloride 


292 


1.118if 


Diphenyl sulfide 



GROUP VII. 



SUB-GROUPS 5 and 6 
Solids 



MELTING-POINT 


BOILING-POINT 


NAME OP COMPOUND 


14° 


251° d. 


Benzenesulfonyl chloride 


28 




Methyl p-toluenesulfonate 


32 


173/15 nun. 


Ethj'l p-toluenesulfonate 


35 




Phenyl benzenesulfonate 


41 


230-5 d. 


Benzyl thiocyanate 


43 




n-Butyl sulfone 


49 




Benzyl sulfide 


52 




Phenyl o-toluenesulfonate 


52-3 




o-Cresyl p-toluenesulfonate 


60 


310 


Phenyl disulfide 


63 




Benzene-m-disulfonj'l chloride 


68 


194/13 mm. 


a-Naphthalenesulfonyl chloride 


69 


145/15 mm. 


p-Toluenesulfonyl chloride 


70 




Phenyl sulfo.xide 


71 




Benzyl disulfide 


75 




p-Bromobenzenesulfonyl chloride 


76 




Trional 


76 


201/13 mm. 


/3-Naphthalenesulfonyl chloride 


80 




Benzenesulfonylmethylaniline 


87 




p-Toluenesulfonylethylaniline 


94 




p-ToluenesulfonylmethylaniUne 


94 




Phenyl p-toluenesulfoate 


94-5 




p-Toluenesulfonylmethylaniline 


98 




Allyl phenyl thiocarbamide 


101 


246 


a-Trithioacetaldehyde 



240 QUALITATIVE ORGANIC ANALYSIS 

GROUP VII. SUB-GROUPS 5 and Q— Continued 



MELTING-POINT 


BOILING-POINT 


NAME OF COMPOUND 


114° 


284° 


Thiophthalic anhydride 


124 




Benzenesulfonyldiphenylamine 


125 


300 d. 


Sulfonal 


125-6 


245-8 


/3-Trithioacetaldehyde 


128 


377 


Diphenyl sulfone 


128 




Dibenzenesulfonylaniline 


133 




Benzyl sulfoxide 


150 




Dibenzyl sulfone 


153 




Thiocarbanilide 


154 




Phenyl thiocarbamide 


216 subl. 




Trithioformaldehyde 



SOLUBILITY TABLE 



SOLUBLE IN WATER- 


-GROUPS I AND 11 


INSOLUBLE IN 


WATER— GROUPS III, IV, V. VI, and VII 














INDIFFERENT COMPOUNDS 










SOLUBLE 




SOLUBLE 


OF C, H, AND C, H, O 






1 


INDIFFERENT 


SOLUBLE IN ETHER 


INSOLUBLE IN ETHER 


IN DILUTE 


IN DILUTE 


SOLUBLE IN 


IW SOLUBLE 


COMPOUNDS 








HCI 




KOH 


COLD CONC. 
HjS04 


IN COLD 

H2S04 


CONTAINING N or S* 


I 




II 


III . 




IV 


V 


VI 


VII 


1. Alcohols (low mol. wt.) 


1. 


Polybasic acids, hy- 
droxy acids, etc. 


1. Primary 


1 


Acids 


1. Alcohols 


1. Saturated 
aliphatic 
hydrocar- 
bons 


1. Nitro compounds (tertiary) 


2. Aldehydes (low mol.) 


2 


Poly hydroxy alcohols. 


2. Secondary 


2 


Phenols 


2. Aldehydes 


2. Aromatic 


2. Amides and negatively sub- 


wt.) 




sugars, and certain 
derivatives 


amines 








hydrocar- 
bons 


stituted amines 


3. Ketones (low mol. wt.) 


3. 


Some amides, amino 


3. Tertiary 


3 


Some am- 


3. Ketones and 


3. Halogen 


3. Nitriles 






acids, amines, etc. 


amines 




ides, imides, 
etc. 


quinones 


derivatives 
of VI, 




4. Other neutral oxygen- 


4 


Many sulfonic acids 


4. Hydra- 


4 


A few nitro 


4. Ethers and 


4. Halogen 


4. Nitrites, nitrates, azo, and 


ated compounds 




and other sulfur com- 
pounds 


zines 




compounds 
and oidmes 


acetals 


derivatives 
of VI2 


hydrazo compounds, etc. 


5. Acids (mostly low mol. 


.5 


Many salts 


5. Miscella- 


5. 


Some thio- 


5. Esters and 




5. Sulfones, sulfonyl deriva- 


wt.) 






neous 




phenols, sul- 
fonic and 
sulfinio acid 


lactones 




tives of secondary amines 


6. A few anhydrides 


G 


Miscellaneous 




6 


A few enols 


6. Anhydrides 




6. Mercaptans, sulfides, sul- 
fates, etc. 


7. A few esters, phenols. 








7 


Miscella- 


7. Unsaturated 




7. Miscellaneous 


etc. 










neous 


hydrocar- 
bons 






8. Amines (mostly low 


















mol. wt.) 


















9. Neutral nitrogen com- 


















pounds 


















10. Miscellaneous 



















* Halogen compounds j 
Simijarly certain nitrogen 



ire not listed separately but are met in each one of the seven groups in accordance with their solubility behavior, 
and sulfur compounds will fall in Groups I, II, III, and IV. See pp. 187, ISS. 



INDEX 



Acenaphthene, 228 

Acenaphthoquinone, 218 

Acetal, 190, 218 

Acetaldehyde, 189 
ammonia, 198 
phenylhydrazine, 238 

Acetaldoxime,a-, 195 

Acetamide, 195, 198 

Acetamino-m-xylene,4-, 235 

Acetanilide, 235 

Acetic acid, 6, 192 
anhydride, 192 

Acetoacetanilide, 235 

Aceto-a-naphthylamine, 236 

Aceto-/3-naphthylamine, 235 

Acetone, 189 

cyanohydrin, 194 
phenylhydrazone, 238 
tests, 154 

Acetonitrile, 194 

Acetophenone, 216, 217 
oxime, 212 
phenylhydrazone, 238 

Acetoxime, 195 

Acetyl-acetone, 190 
-m-aminobenzoic acid, 208 
-p-aminobenzoic acid, 208 
-aminophenol,p-, 236 
-o-aminophenol, N-, 211 
-p-aminophenol,N-, 211 
-p-anisidine, 235 
-anthraniUc acid, 207 
bromide, 191 
-n-butylaniUne, 234 
chloride, 191 



Acetyl diphenylamine, 235 

methyl urea,s-, 198 

-p-methylaminophenol,N-, 211, 236 

methyl-o-toluidine, 234 

methyl-p-toluidine, 235 

-phenylglycine, 207, 208 

phenylhydrazine,s-, 235 

piperidine, 194 

n-propylaniline, 234 

-salicylic acid, 207 

-m-toluidine, 234 

-o-toluidine, 235 

-p-toluidine, 236 

urea, 198 
Acetylene-dicarboxylic acid, 193 

dichloride, 228 
Acid phthalates, 152 
Acidic compounds, 54 

groups, 22 

nitrogen, 67 
Acids, aliphatic, 6 

solubility of, 26 
Aconitic acid, 196 
Acridine, 203 
Acrolein, 189 
Acrylic acid, 192 
Acyl halides, 41, 135 
Acylation of amines, 59 
Adipic acid, 207 
Alanine, 87, 198 
Alcohol test, 136 
Alcohols, 48, 51 

solubility of, 24 
Aldehydes, 42, 43, 46, 142 

solubility of, 26 
Alizarin, 211 
Alkaloids, 94 




242 



INDEX 



Alloxan, 198 

AUyl acetate, 190, 220 
alcohol, 189 
-amine, 193 
benzene, 226 
benzoate, 222 
bromide, 228 
chloride, 228 
formate, 189 
iodide, 229 

isothiocyanate, 78, 239 
phenyl thiocarbamide, 239 
sulfide, 238 
thiocarbamide, 195 

Amide formation, 157 
test, 138 

Amides, 71 

Amine, derivatives, 160-1 
tests, 59, 144 

Amino-acetanilide,;;,- 203 
-acetophenone,p-, 203 
acids, aliphatic, 87, 102 
acids, aromatic, 92 
-anthraquinone, 1-, 204 
-anthraquinone,2-, 204 
-azobenzene,p-, 203 
-5-azotoluene,2-, 203 
-benzenesulfonic acid,p-, 204 
-benzoic acid,m-, 204, 207 
-benzoic acid,p,- 204, 208 
-benzoic acids, 18 
-n-caproic acid,dl-,a-, 204, 207 
-caprylic acid,dl-,a-, 204, 209 
-cinnamic acid,o-, 207 
-cinnamic acid,p-, 207 
-o-cresol,5-, 204 
-ethyl alcohol,/3-, 197 
-2-hydroxytoluene,5-, 211 
-isobutyric acid,a-, 198 
-naphthalene sulfonic acid, 213 
-phenol,m-, 194, 198, 203, 211 
-phenol,o-, 194, 198, 204, 211 
-phenol,p-, 204, 211 
-phenylacetic acid,rW-,a-, 208 
-salicylic acid,5-, 204, 209 
-n-valeric acid,dl-,a-, 204, 209 
-TO-xylene,4-, 200 

Amino-p-xylene, 200, 201 



Ammoniacal AgNOs, 142 

Amygdalin, 197 

Amyl alcohol, n-, 24, 215 

alcohol,se'c-, 190, 215 

alcohoMerf-, 190, 215 

-amine, n-, 193 

bromide, <erf-, 229 

chloride, <er<-, 229 

ether,n-, 219 

iodide,tert-, 229 

methyl ether,n-, 218 
Amylene, 226 
Analysis: acids, 138 

alkoxyl group, 72 

amine group, 174 

Beilstein test, 124 

carbonyl group, 171 

carboxyl group, 172 

Carius method, 124 

elements, 121 

ester group, 140, 172 

halogen estimation, 168 
test, 123 

hydroxyl group, 171 

ignition test, 132 

Kjeldahl method, 167 

metals, 169 

nitrogen test, 123 

saponification, 172 

sodium decomposition, 122 

sulfur test, 123 

unsaturation, 170 

Zeisel method, 172 
Anethole, 219, 220 
Angelica lactone,a-, 221 

lactone,/3-, 190 
Anhydrides, 47 
Aniline, 200 
Anisaldehyde, 216 
Anisic acid, 207 

alcohol, 217 
Anisidine,o-, 200 

,p-, 202 
Anisole, 218 
Anisyl chloride, 225 
Anthra-cene, 228 

quinone, 218 
Anthra quinonylhydrazine, 205 



INDEX 



243 



AnthranUic acid, 203, 207 

Antipyrine, 195, 198 

Apiole, 220 

Arabinose,/-, 197 

Arbutin, 211 

Aromatic hydrocarbons, 35, 134, 135 

Aryl hydrazones, 153 

Asparagine,d-, 198, 204, 208 

,1-, 198, 204, 208 
Aspartic acid,?-, 198 
Atropine, 95, 203 
Aurin, 211 
Azo-benzene, 238 

compounds, 71-2, 

-phenetole,o-, 238 

-phenetole,p-, 238 

-phenol,o-, 211 

-phenol,p,- 211 

-toluene,o-, 238 

-toluene, p-, 238 
Azoxy-benzene, 238 

compounds, 71-2 

-toluene,o-, 238 

-toIuene,p,- 238 



B 

Barbituric acid, 198 
Basic groups, 19, 59 
Beilstein test, 124 
Benzal-acetone, 216, 217 

-acetophenone, 217 

-amino-o-cresol,5-, 211 

-aminophenol,p-, 211 

-aniline, 234 

-azine, 238 

chloride, 230 

-doxime,a-, 212 
Benzaldehyde, 215 

phenylhydrazone, 238 
Benzamide, 235 
Benzamidine, 202 
Benzanilide, 236 
Benzene, 227 

-azo-o-cresol, 211 

-m-disulfonylchloride, 239 

-sulfinic acid, 195, 213 



Benzene-sulfcnamide, 213 
-sulfonic acid, anhydr., 199 
-sulfonic acid, hydr., 199 
-sulfonyl benzylamine, 213 
-sulfonyl chloride test, 144, 239 
-sulfonyl TO-nitraniline, 213 
-sulfonyl o-nitraniline, 213 
-sulfonyl p-nitraniline, 213 
-sulfonyl TO-toluidme, 213 
-sulfonyl o-toluidine, 213 
-sulfonyl p-toluidine, 213 
-sulfonylaniline, 213 
-sulfonylchloraniline, 213 
-sulfonyldiphenylamine, 240 
-sulfonylmethylaniline, 239 

Benzidine, 203 
rearrangement, 73 

BenzU, 217 
dioxime,a-, 212 

Benzilic acid, 207 

Benzine, 227 

Benzoic acid, 207 
anhydride, 206, 225 
sulfimide, o-, 213 

Benzoin, 217 

Benzo-nitrile, 237 
-phenone, 217 
-phenone oxime, 212 
-phenone phenylhydrazone, 238 
-quinone, 191, 217 
-o-toluidide, 235 
-p-toluidide, 236 
-trichloride, 230 

Benzoyl-acetone, 214 
alanine,riZ-, 207 
bromide, 225 
carbinol, 191 
chloride, 225 
-a-naphthylamine, 236 
peroxide, 225 
phenylhydrazine, 236 
piperidine, 234 

Benzyl acetate, 222 
alcohol, 216 
-amine, 26, 194 
-aniline, 201 
benzoate, 223 
bromide, 230 



244 



INDEX 



Benzyl n-butyl ether, 219 

TC-butyrate, 222 

carbamate, 235 

carbamide, 235 

chloride, 149, 230 

cinnamate, 224 

disulfide, 239 

ethyl ether, 219 

ethylaniline, 201 

isobutyl ether, 219 

malonic acid, 193, 207 

mercaptan, 239 

methyl ether, 219 

methylaniline, 201 

oxalate, 224 

phthalate, 224 

salicylate, 223 

succinate, 224 

sulfide, 239 

sulfoxide, 240 

thiocyanate, 239 
Retain, 198 
Biuret, 198, 236 
Boiling-points, 117 
Borneol,d-, 218 
Bornyl acetate, 222, 224 

chloride, 231 
Bromal, 190 

alcoholate, 191 

hydrate, 191 
Bromine-water test, 137 
Bromo-acetanilide,p-, 236 

-acetic acid, 192 

-acetophenone, CO-, 217 

-acetyl bromide, 192 

-acetyl chloride, 192 

-4-acetylaminotoluene,3-, 235 

-4-arainotolucne,3-, 201 

-aniline,TO-, 201 

-aniline,o-, 201 

-aniline, 7^-, 202 

-anisole,o-, 219 

-anisole,p-, 219 

-benzamide,m-, 236 

-benzamide,o-, 236 

benzamide,p-, 236 

-benzene, 229 

-benzenesulfonyl chloride, p-, 239 



Bromo-benzolc acid,7/i-, 18, 207 

-benzoic acid,o-, 18, 207 

-benzoic acid,p-, 18, 208 

-benzyl chloride,o-, 230 

-benzyl chloride, ;>, 231 

-n-butyric acid,a-, 18, 206 

-rf-camphor,a-, 217 

-cyclohexane, 230 

-2, 4-dinitrobenzene, 233 - 

-form, 229 

-hydroquinone, 193, 210 

-isovaleryl urea,a- 235 

-naphthalene, a-, 230 

-naphthalene,/^-, 231 

-nitrobenzene, m-, 18, 233 

-nitrobenzene,o-, 18, 232 

-nitrobenzene, p-, 18, 233 

-phenetole,o-, 219 

-phenetole,p- 219 

-phenol, m-, 209, 210 

-phenol,o-, 209 

-phenol, p-, 210 

-phenylhydrazine,p-,205 

-propionic acid,a-, 192, 206 

-propionic acid,^-, 192 

-styrene,co-, 230 

-toluene, /«-, 230 

-toluene,o-, 230 

-toluene,p,- 230, 231 

-n-valeric acid,a-, 206 
Brucine, 204 
Butyl acetate, n-, 220 

acetate,sec-, 220 

alcohol, n-, 24, 50, 190 

alcohol,sec-, 189 

sdcoho\,tert-, 189, 191 

-amine,n-, 193 

-amine,sec-, 193 

-aniline, n-, 200 

benzoate,n-, 223 

bromide, n-, 229 

bromide,/er<-, 228 

n-butyrate,n-, 221 

carbamate,7i-, 234 

carbonate,n-, 216 

chloralhydrate, 217 

chloride,n-, 229 

chloride,<er<-, 226 



INDEX 



245 



Butyl chloroacetate,n-, 221 

chlorocarbonate,n-, 221 

o-cresyl ether, n-, 219 

ether,n-, 218 

formate,/!-, 220 

iodide,n-, 229 

iodide,sec-, 229 

iodide,tert-, 229 

mercaptan,7i-, 238 

o-methoxybenzoate,n-, 223 

methyl carbinol,n-, 215 

nitrate,n-, 237 

nitrite,n-, 237 

oxalate,/!-, 222 

oxamate,ri-, 235 

phenylacetate,rt-, 222 

phenyl ether,n-, 219 

salicylate, n-, 223 

sulfide,/!-, 239 

sulfone,n-, 239 

tartarate,n-, 223 
Butyr-aldehyde,n-, 189, 218 

-amide,n-, 195, 198 

-anilide,/!-, 235 
Butyric acid,n-, 6, 192 

anhydride,/!-, 206, 225 
Butyronitrile,/!-, 237 
Butyryl chloride,/!-, 191, 225 



Caffeine, 93, 198, 204 

Camphene,^, 226 

Camphor,^-, 218 
,dl-, 218 
oxime,d-, 212 
-phenylhydrazone, 237 
sulfonic acid, 199 
sulfonic acid,c?-, 199 

Camphoric acid,d-, 208 
anhydride, d-, 225 

Camphorquinone, 218 

Capric acid, 206 

Caproic acid,n-, 206 

Caprjdic acid,/!-, 206 

Carbamide, 198 

Carbanilide, 236 



Carbohydrates, 82, 155 
Carbon disulfide, 76, 238 

tetrabromide, 231 

tetrachloride, 229 
Carbonyl group, 171 
Carboxyl group, 57, 172 
Carius method, 124 
Carvacrol, 209 
Catechol, 193 
Cetyl alcohol, 217 
Characterization of compounds, 2 
Chloral, 101, 189 

alcoholate, 191 

-formamide, 195 

hydrate, 191 
Chloranil, 218 
Chloro-acetanilide,/)-, 236 

-acetic acid, 192 

-acetone, 190 

-acetophenone, o)-, 217 

-acetyl bromide, 192 

-acetyl chloride, 191 

-aniline,//!-, 200 

-aniline,o-, 200 

-aniline, p-, 202 

-anisole,o-, 219 

-anisole,p-, 219 

-benzaldehyde,//!-, 216 

-benzaldehyde,o-, 216 

-benzaldehyde, p-, 217 

-benzene, 229 

-benzoic acid,r/!-, 207 

-benzoic acid,o-, 207 

-benzoic acid,p-, 208 

-benzoic acids, 18 

-benzyl bromide,p-, 231 

-benzyl chloride,o-, 230 

-benzyl chloride, p-, 230 

-l-bromoethane,l-, 229 

-/>!-cresol,6-, 210 

-cyclohexane, 229 

-2, 4-dinitrobenzene, 232 

-ethyl acetate, /3-, 221 

-ethyl ether, 191 

-form, 228 

-hydroquinone, 193 

-methyl ether, 191 

-methylethyl ether, 191 



246 



INDEX 



Chloro-naphthalene,a-, 230 

-naphthalene,-^, 230 

-nitrobenzene, 18 

-nitrobenzene,™-, 232 

-nitrobenzene,o-, 232 

-nitrobenzene, p-, 233 

-phenetole,o-, 219 

-phenetole,p-, 219, 220 

-phenol,m-, 209, 210 

-phenol,o-, 209 

-phenol, p-, 210 

-picrin, 232 

-propionic acid,a, 192 

-propionic acid,i3, 192 

-toluene,m-, 229 

-toluene,o-, 229 

-toluene, p-, 229 

-toluenes, 149 
Cholesterol, 218 
Choline, 198 
Cinchonidine, 204 
Cinchonine, 204 
Cineol, 219 
Cinnam-aldehyde, 216 

-amide, 235 
Cinnamic acid, 207 

anhydride, 225 
Cinnamonitrile, 237 
Cinnamoyl chloride, 225 
Cinnamyl alcohol, 216, 217 

cinnamate, 224 
Citraconic acid, 196 

anhydride, 225 
Citral, 216 
Citric acid, 196 
Citronellal, 216 
Classification reactions : 

Acetylene derivatives, 34 

Acidic compounds, 54 

Acidic nitrogen, 67 

Acids, 55, 57 "^ 

Acyl halides, 41, 135 

Acylation of amines, 59 

Alcohols, 48, 51, 136 

Aldehydes, 42, 43, 46 

Aliphatic hydrocarbons, 34, 134 

Amides, 71, 145, 146 

Amines, 61, 144 



Classification reactions: 
Ammoniacal AgNOs, 142 
Anhydrides, 47 
Aromatic hydrocarbons, 35, 134, 

135 
Azo compounds, 71, 72 
Azoxy compounds, 71, 72 
Basic nitrogen, 59 
Benzenesulfonyl test, 144 
Bromine addition, 32 
Bromine test, 137 
Carbohydrates, 82 
Carboxyl group, 57 
Diazonium compounds, 67 
Diazotization, 63, 144 
Dimethylsulfate test, 135 
Duclaux values, 57, 139 
Enols, 43 
Esters, 47, 140 
Ethers, 48 

Fehling's solution, 83, 143 
Ferric chloride test, 56, 137 
Fuchsin test, 46, 142 
Furfural formation, 86 
Halogen compounds, 38, 135 
Hydrazines, 66, 71 
Hydrazo compounds, 71, 73 
Hydrolysis test, 145, 146 
Imides, 71 

Indifferent nitrogen, 68 
Iodoform test, 53, 137 
Isocyanates, 71 
Ketones, 42, 43, 46 
Neutral equivalent, 138 
Nitriles, 71 

Nitro compounds, 71, 72, 145, 146 
Nitroso compounds, 71, 72 
Osazones, 71, 84, 85, 144, 155 
Oximes, 71 
Pentoses, 86 
Phenols, 55, 57, 136 
Phenylhydrazones, 44, 142, 143 
Phenylisocyanate test, 50 
Phthalein formation, 137 
Phthalic anhydride test, 51, 62 
Reactive esters, 53 
Reactive methylene, 43 
Reducing agents, 69 



INDEX 



247 



Classification reaction: 

Reduction tests, 145 

Saponification equivalents, 140 

Semicarbazones, 71 

Silver nitrate test, 46, 135, 142 

Starches, 87 

Sulfides, 76 

Sulfite addition, 45, 141 

Sulfonation test, 134 

Sulfones, 77 

Sulfonic acids, 78 

Sulfoxides, 77 

Sulfur compounds, 75 

Sulfuric acid test, 30 

Tertiary alcohols, 50 

Tertiary amines, 65 

Thiols, 76 

Unsaturation test, 31, 133, 134 

Van Slyke method, 88 

Volatility constants, 57 
Cocaine,/-, 203 
Codeine,/-, 203 
Coniferin, 218 
Confine, 95, 200 
Coumaric acid,o-, 208 

acid,p-, 208 
Coumarin, 224 
Creatin, 204 
Creatinin, 94, 198 
CresoI,m-, 209 

,0-, 209, 210 

,p-, 209, 210 

-phthalein,o-, 211 

-sulfonephthalein,o-, 213 
Cresyl acetate,o-, 221 

benzoate,m-, 224 

benzoate,o-, 223 

benzoate,p-, 224 

methyl ether, m-, 219 

methyl ether,o-, 219 

methyl ether, p-, 219 

p-toluenesulfonate,o-, 239 
Crotonic acid,Q:-, 192 
Cumene, 227 
Cyanamide, 194 
Cyano-acetic acid, 192 
Cyano-benzoic acid,p-, 208 

-hydrins, 71 



Cyanuric acid, 212 

Cyclo-heptanone, 215 
-hexane, 190, 227 
-hexanol, 215, 216 
-hexanone, 190, 215 
-hexylacetate, 221 
-hexylamine, 194 
-pentadiene, 226 
-pentanol, 215 
-pentanone, 215 

Cymene,p-, 32, 227 

Cystine, 87, 213 



D 



Decyl alcohol,?*-, 216 
Dehydracetic acid, 214 
Derivatives: 
Acetone, 154 
Acid phthalates, 152 
Acids, 157 
Alcohols, 150 
Aldehydes, 153 
Amines, 160, 161 
Anhydrides, 160 
Carbohydrates, 155 

acetyl derivatives, 156 

hydrazones, 156 

mucic acid, 156 

osazones, 155 
Characteristics, 148 
Dinitrobenzoates, 151 
Diphenylurethanes, 159, 160 
Esters, 157, 158, 160, 164 
Glycol benzoates, 151 
Halogen compounds, 163, 165 
Hydrocarbons, 163, 165, 166 
Nitrogen compounds, 161 
Osazones, 155 

Oxidation of side-chains, 165 
Oxidation products, 152, 154 
Oximes, 153 
Phenols, 159 
Phenylhydrazones, 153 
Phthalimides, 164 
Picrates, 166 
Semicarbazones, 153 



248 



INDEX 



Derivatives : 

Solid esters, 158, 164 

Toluidides, 157 

Urethanes, 152 
Dextrins, 197 
Dextrose, 197 
Diacetin, 190, 196 
Diacetone alcohol, 190 
Diacetyl, 189 

-dioxime, 212 

-N-methyl-p-aminophenol, 233 

-monoxime, 195 

morphine, 204 

-7w-phenylenediamine, 236 

-o-phenylenediamine, 236 

-7>phenylenediamine, 236 
Diallyl, 226 

-amine, 194 
Diamino-chlorobenzene,2,4-, 202 

-diphenylmethane, /);/-, 202 

-phenol,2,4-, 194, 198 
Diazoaminobenzene, 238 
Diazotization, 63, 67, 144 
Dibenzenesulfonylaniline, 240 
Dibenzoylmethane, 214 
Dibenzyl, 228 

-amine, 201 

-aniline, 202 

-carbamide, 236 

ether, 219 

-idineacetone, 217 

ketone, 216 

sulfone, 240 
Dibromo-aniline,2,4-, 202 

-benzene,/??-, 230 

-benzene,o-, 230 

-benzene,/^-, 231 
solubility, 11 

-butane, 1,2-, 229 

-naphthalene, 1,2-, 231 

-propionic acid,a,/3-, 192 

-thymolsulfonephthalein, 213 
Dibutyl carbonate, 222 

oxalate, 219 
Di-w-butyl carbinol, 215 
Di-7J-butylamine, 200 
Di-n-butylaniline, 201 
Dicarboxylic acids, 16 



Dichloro-acetamide, 235 

-acetic acid, 192 

-acetone,a, 190 

-acetone,a7-, 217 

-aniline,2,4-, 202 

-azoxybenzene, pp'-, 238 

-benzaldehyde,2,4-, 217 

-benzene,//;-, 230 

-benzene,o-, 230 

-benzene,p-, 231 

-benzene sulfonic acid,2,5-, 199 

-diethyl ether,a,a'-, 191 

-ethyl carbonate,/3,/3'-, 222 

-ethyl ether,a;,a'-, 218 

ethyl ether,a,/3-, 218 

-ethyl ether,^,^'-, 219 

-hydroquinone, 211 

-methyl ether,a,a'-, 191 

-4-nitroaniline,2,6-, 234 

nitrobenzene,2,5-, 232 

-phthalic acid,3,6-, 208 

-propane,2,2-, 228 

-propyl carbonate,7,7 -, 223 

-toluene,2,4-, 230 
Dicyano-diamide, 198 

-diamine, 198 
Dielectric constants, 12 
Diethyl-amine, 193 

-aminoethyl alcohol,/3-, 194 

-aminopropyl alcohol, 7-, 194 

-aniline, 200 

barbituric acid, 212 

benzene,/n-, 227 

benzene,o-, 227 

benzene, p-, 227 

bromoacetyl carbamide, 235 

-carbanilide, 235 

ketone, 189, 215 

sulfate, 239 
Diglycohde, 191, 224 
Dihydronaphthalene, 220 
Dihydroxy-naphthalene,l,2-, 210 

-naphthalene, 1,4-, 211 

-naphthalene, 1,8-, 211 

-stearic acid, 207 
Diiodobenzcne,p-, 231 
Diiso-amyl, 227 

-amylamine, 200 



INDEX 



249 



Diiso-propyl ether, 218 
Dimethyl-acetal, 189, 218 

-amine, 193 

-amino-4-aminobenzene,l-, 202 

-aminobenzaldehyde,^-, 202 

-aminoazobenzene,p,- 203 

-2-aminobenzene,l,4-, 200 

-4-aminobenzene,l,3-, 200 

-aminoethyl alcohol,/^-, 194 

-aminophenol,m-, 210 

-ammophenol,p-, 202, 210 

-aniline, 200 

benzylamine, 200 

carbanilide, 235 

quinoline,2,4-, 201 

quinoline,2,6-, 202 

sulfate, 135, 239 

sulfone, 195 

-o-toluidine, 200 

-p-toluidine, 200 
Dinitro-6-aminophenol,2,4-, 211 

-aniline,2,4-, 204, 236 

-aniline,2,6-, 203, 235 

-benzamide,3,5-, 234, 236 

-benzene,m-, 233 

-benzenes, 18 

-benzoates, 151 

-benzoic acid,2,4-, 207 

-benzoic acid,3,5-, 208 

-hydroquinone diacetate, 233 

-naphthalene, 1,5-, 234 

-phenol,2,4-, 210 

-toluene,2,4-, 233 

-toluene,2,6-, 233 

-toluene,3,5-, 233 

-m-xylene,4,6-, 233 
Dioleine, 224 
Dipalmitine, 224 
Dipentene, 220 
Diphenyl, 228 

-amine, 234 

-bromomethane, 231 

-carbamide chloride, 225 

carbonate, 224 

-dichloromethane, 230 

ether, 219, 220 

-ethylenediamine, 202 

-ethy]enediamine,s-, 203 



Diphenyl-hydrazine,as-, 205 

-methane, 227, 228 

nitrosoamine, 238 

-piperazine, 204 

sulfide, 239 

sulfone, 240 

urethanes, 159, 160, 234 
Di-?!-propylamine, 193, 200 
Di-n-propylaniline, 201 
Distearine, 224 
Di-p-tolyl ketone, 217 
Di-p-tolylamine, 234 
Duclaux constants, 57, 139 
Dyes, 96 



E 



Elaidic acid, 206 
Elementary analysis, 121 
Enols, 43 

Epichlorohydrin, 215, 218 
Esters, 47, 140, 158, 160, 164, 172 

solubility of, 26 
Estimation, see Analysis 
Ethers, 48 
Ethyl acetanilide,N-, 234 

acetate, 189, 220 

acetoacetate, 214, 221 

aconitate, 223 

adipate, 222 

alcohol, 24, 50, 189 

-amine, 193 

-m-aminobenzoate, 201 

-p-aminobenzoate, 202 

-aniline, 200 

anisate, 223 

anthranilate, 201 

benzene, 227 

benzoate, 222 

benzylacetoacetate, 223 

benzylamine, 200 

benzylmalonate, 223 

bromide, 228 

bromoacetate, 221 

bromomalonate, 222 

a-bromopropionate, 221 

n-butylmalonate, 222 



250 



INDEX 



Ethyl di-n-butylmalonate, 216, 222 
n-butyrate, 220 
caprate, 222 
w-caproate, 221 
caprylate, 222 
carbamate, 195 
carbonate, 190, 220 
chloride, 228 
chloroacetate, 221 
chlorocarbonate, 220 
chloroformate, 191 
a-chloropropionate, 221 
cinnamate, 223, 224 
cyanoacetate, 237 
dibenzylmalonate, 223, 224 
dichloroacetate, 221 
diethylmalonate, 222 
disulfide, 239 
ether, 189, 218 
ethylacetoacetate, 222 
ethylmalonate, 222 
formate, 189, 191 
gallate, 211 
glutarate, 222 
n-heptylate, 221 
hippurate, 234 
iodide, 228 
isobutyrate, 220 
isovalerate, 221 
lactate, 190, 221 
laurate, 223 
levulinate, 222 
malonate, 222 
malonic acid, 193 
mandelate, 224 
mercaptan, 195, 238 
methyl ketone, 189 
methylacetoacetate, 221 
methylaniline, 200 
methylketoxime, 194 
methylmalonate, 222 
-/3-methyl carbamate, 234 
-a-naphthyl carbamate, 234 
nitrate, 194, 237 
nitrite, 194, 237 
TO-nitrobenzoate, 232 
orthoformate, 190, 218, 221 
oxalate, 190, 221 



Ethyl oxamate, 235 

oxanilate, 234 

oxide, 189 

phenacetin,N-, 234 

phenoxyacetate, 223 

phenylacetate, 222 

phenylcinchoninate, 202 

phthalate, 223 

propionate, 189, 220 

pyruvate, 190 

saUcylate, 209, 222 

sebacate, 223 

succinate, 222 

sulfide, 238 

sulfite, 239 

tartarate, 223 

thiocyanate, 238 

p-toluenesulfonate, 239 

-o-toluidine,N-, 200 

-p-toluidine,ISi;-, 200 

trichloroacetate, 221 

trichlorolactate, 224 

n-valerate, 221 
Ethylal, 189, 218 
Ethylene bromide, 229 

bromohydrin, 190 

chloride, 229 

chlorobromide,s,- 229 

chlorohydrin, 190 

-diamine, 197 

glycol, 196 

-glycoldiacetate, 221 

iodide, 231 
Ethylidene bromide, 229 

chloride, 228 
Eugenol, 209 

methyl ether, 219, 224 
Exhaustive methylation, 95 



F 



Fehling's solution test, 83, 143 
Ferric chloride test, 56, 137 
Fluorene, 228 
Fluorescein, 211 
Formalin, 189 
Formamide, 194, 197 



INDEX 



251 



Formanilide, 195, 234 
Formic acid, 6, 191 
Formyl diphenylamine, 234 

piperidine, 194 
Fuchsin test, 46 
Fumaric acid, 17, 208 
Furfural, 190 

formation, 86 
Furfuramide, 235 
Furfuryl alcohol, 190 

G 

Galactose,cZ-, 197 
Gallic acid, 208 
Gasoline, 227 
Geraniol, 216 
Glucosamine,^-, 197, 198 
Glucose, 197 
Glutaric acid, 196 
Glycerol, 196 

a-bromohydrin, 196 

a-chlorohydrin, 196 

Qf-dibromohydrin, 216 

)3-dibromohydrin, 216 

a-dichlorohydrin, 190, 215 

/3-dichlorohydrin, 190, 215 

tribromohydrin, 230, 231 

tributyrate, 223 

trichlorohydrin, 229 
Glycocoll, 87, 198 
Glycogen, 197 
Glycol dibenzoate, 224 
Glycolic acetal, 190 

acid, 192, 196 

aldehyde, 197 
Glycyl alanine, 89 
Guaiacol, 209, 210 

benzoate, 224 

carbonate, 224 
Guanidine, 198 
Guanine, 93, 204 

H 

Halogen compounds, 38, 135, 163, 165 

estimation, 168 
Helicin, 197 



Heptyl alcohol,n-, 24, 215 

aldehyde,n-, 215 

bromide,?!-, 230 
Hexachloro-benzene, 231 

-ethane, 231 
Hexahydrobenzoic acid, 206 
Hexamethylenetetramine, 198 
Hexane,n, 227 
Hexyl alcohol,?!-, 24, 215 

alcohol, sec-, 215 

aldehyde,?!-, 215 

methyl carbinol,?!-, 215 
Hippuric acid, 208 
Histidine, 87 
Homologj', 5 
Hydantoin, 93, 198 
Hydrazines, 66 

Hydrazinobenzoic acid,p-, 205, 208 
Hydrazo-benzene, 238 

compounds, 71, 73 

-toluene,o-, 238 
Hydrazones, 71, 153, 156 
Hydro-benzamide, 235 

-cinnamic acid, 206 

-quinone, 193 

-quinone diacetate, 225 

-quinone dimethyl ether, 220 

-quinone monomethyl ether, 210 
Hydrocarbon test, 134, 163, 165 
Hydrolysis test, 145, 146 
Hydroxy-acids, 102 

-azoxybenzene,p-, 211 

-benzaldehyde,?w-, 210 

-benzaldehyde,p-, 210, 217 

-benzamide,?w-, 211 

-benzamide,p-, 211 

-benzoic acid,???-, 18, 208 

-benzoic acid,o-, 18 

-benzoic acid,;?-, 18, 208 

-benzyl alcohol,o-, 191 

-butyric acid,a-, 196 

-ethyl acetate,/3-, 190 

-ethylbenzoate,?n-, 210 

-ethylbenzoate,p-, 210 

-mesitylene, 210 

-methylbenzoate,7?-, 211 

-3-naphthoic acid,2-, 208 

-l-naphthylaldehyde,2-, 210 



252 



INDEX 



Hydroxy-phenylglycine,p-, 208 
-(luinoline,2-, 204, 211 
-quinoline,8-, 202, 210 
-wi-toluic acid, 2-, 207 
-w-tohiic acid,4-, 207, 211 

Hydroxy 1 group, 171 

I 

Imides, 71 
Indene, 226, 227 
Index of refraction, 119 
Indifferent nitrogen, 68 
Indol, 202 
Inert solvents, 9 
Inosite,i-, 197 
Inulin, 197 

Inversion of sucrose, 86 
Iodo-acetanilide,p-, 236 

-acetic acid, 192 

-aniline, m-, 201 

-aniline,o-, 202 

-aniline, p-, 2C2 

-benzamide,??)-, 236 

-benzamide,o-, 236 

-benzainide,p-, 236 

-benzene, 230 

-benzoic acid,o-, 207 

-benzoic acid,/;-, 208 

-benzoic acids, 18 

-form, 231 

-form test, 53, 137 

-propionic acid, fi-, 192 

-toluene,??!-, 230 

-toluene,o-, 230 

-toluene,/;-, 230, 231 
Ionization constants, 20, 21 
Isatin, 212 
Isoamyl acetate, 221 

alcohol, 24, 50, 190, 215 

-amine, 193 

-aniline, 201 

benzoate, 223 

bromide, 229 

butyrate, 221 

carbamate, 234 

carbonate, 234 

cbloride. 229 



Isoamyl ether, 219 

formate, 220 

iodide, 229 

isovalerate, 222 

nitrate, 237 

nitrite, 237 

oxalate, 223 

propionate, 221 

salicylate, 209, 223 

succinate, 223 
Isoamylene, 226 
Isobutyl acetate, 220 

alcohol, 24, 50, 190 

-amine, 193 

benzoate, 222 

bromide, 229 

n-butyrate, 221 

chloride, 228 

formate, 220 

iodide, 229 

isobutyrate, 221 

methyl ketone, 215 

nitrate, 237 

nitrite, 237 

phenylacetate, 222 

propionate, 221 

succinate, 223 
Isobutyr-aldehyde, 189 

amide, 195, 198 
Isobutyric acid, 6, 192 
Isobutyronitrile, 194, 237 
Isobutyryl chloride, 191 
Isocaproic acid, 206 
Isocapronitrile, 237 
Isocrotonic acid, 192 
Isocyanates, 71 
Isoeugenol, 209 
Isomaltose, 197 
Isonicotinic acid, 204, 209 
Isopentane, 227 
Isophthalic acid, 209 
Isopropyl acetate, 189 

alcohol, 24, 50, 189 

-amine, 193 

benzoate, 222 

bromide, 228 

?i-butyrate, 221 

chloride, 228 



INDEX 



253 



Isopropyl formate, 189 

iodide, 229 

methyl ketone, 189 

oxalate, 222 

phthalate, 223 

tartarate, 223 
Isoquinoline, 201 
Isosafrole, 219, 226 
Isovaleraldehyde, 215 
Isovaleranilide, 235 
Isovaleric acid, 192, 206 
Isovaleryl chloride, 191, 225 
Itaconic acid, 196 



Kerosene, 227 

Ketones, 26, 42, 43, 46, 153 

Kjeldahl analysis, 167 



Laboratory notes, 110, 130, 132 
Lactic &cid,dl-, 196 
Lactide, 191, 225 
Lactonitrile, 194 
Lactose, 197 
Lsevulose, 197 
Laurie acid, 206 
Lauryl alcohol, 216, 217 

bromide, 230 
Leucine, 87 

Leucomalachite green, 203 
Levnlinic acid, 101, 192 
Liebermann reaction, 72 
Ligroin, 227 
Limonene, 226 
Linalool,?-, 215 
Linalyl acetate, 222 
Lysine, 87 

M 

Maleic acid, 17, 193, 196 

anhydride, 225 
Malic acid,Z-, 196 
Malonamide, 198 
Malonic acid, 193 

acids, 101, 158 
Maltose, 197 



Mandelic acid,f^-, 193 

acid,/-, 193 

acid,dl-, 193 
Mandelonitrile, 237 
Mannitol,d-, 197 
Mannose,d-, 197 
Melamine, 204 
Melting-points, 114 
Menthane,p, 227 
Menthene, 226 
Menthol,/-, 217 
Menthone,/-, 216 
Menthyl acetate, 222 

-amine,/-, 200 

-benzoate,/-, 224 
Mesidine, 200 
Mesityl oxide, 215 
Mesitylene, 227 
Metaldehyde, 217 
Method of analysis, 4, 108 
Methoxy-benzaidehyde,o-, 216, 217 

-benzoyl chloride, o-, 225 

-quinoline,6-, 201 
Methyl acetanilide, 203, 235 

acetate, 189, 191 

acetoacetate, 190, 214, 221 

aconitate, 232 

alcohol, 24, 50, 189 

-amine, 193 

-aminophenol,o-, 202, 210 

-aminophenohp-, 202, 210 

-7;-aminophcnol,N-, 194 

n-amyl ketone, 215 

-aniline, 200 

anisate, 224 

anthranilate, 201 

anthranilic acid,N-, 207 

anthraquinone,2-, 218 

benzoate, 222 

benzylamine, 200 

bromoacetate, 190, 22 

butene-1, 226 

7i-butyrate, 190, 220 

caprate, 222 

caprylate, 221 

carbamate, 195 

carbonate, 189, 220 

chloroacetate, 190, 221 



254 



INDEX 



Methyl chlorocarbonate, 220 
chloroformate, 191 
cinnamate, 223, 224 
citrate, 191, 225 
cyclohexane, 227 
cyclohexanols, 215 
cyclohexene,2-, 226 
cyclohexene,3-, 226 
cyclohexene,4-, 226 
diphenylamine, 201 
ether salicylic acid, 206 
ethyl acetoacetate, 221 
formate, 189, 191 
-d-glucoside,a-, 197 
n-heptylate, 221 
?n-hydroxybenzoate, 210 
iodide, 228, 230 
isobutyrate, 189, 220 
isovalerate, 220 
lactate, 190 
laurate, 222 
levulinate, 190, 221 
malonate, 190, 221 
malonic acid, 193 
mandelate, 224 
o-inethox>'benzoate, 222 
methylacetoacetate, 221 
N-methylanthranilate, 200 
methylmalonate, 221 
myristate, 224 
naphthalene,^-, 227 
naphthalene,|3-, 227, 228 
naphthylamine,a-, 201 
nitrate, 194, 237 
-nitrobenzoate, 232, 233 
orthoformate, 189, 218 
oxalate, 192 
palmitate, 224 
phenacetin,N-, 234 
phenoxyacetate, 223 
phenyl carbinol, 216 
phenylacetate, 222 
phenylhydrazine,as-, 205 
phthalate, 223 
propionate, 189 
n-propyl carbinol, 215 
propyl ketone, 189, 215 
pyruvate, 190 



Methyl quinoline,6-, 201 

red, 207 

salicylate, 209 

sebacate, 223 

stearate, 224 

succinate, 190, 191 

sulfate, 195 

sulfide, 238 

sulfite, 238 

tartarate, 191 

thiocyanate, 238 

p-toluenesulfonate, 239 

-p-toluidine,N-, 200 

-p-tolyl ketone, 216 

urea, 198 

w-valerate, 221 
Methylal, 189, 218 
Methylene-amine acetonitrile, 203, 
237 

bromide, 229 

chloride, 228 

-disalicylic acid, 208 

iodide, 230 
Mixtures, 176 
Molecular weight, 120 
Mono-acetin, 196 

-bromoacetal, 219 

-chloroacetal, 218 

-oleine, 224 

-palmitine, 224 

-stearine, 224 
Morphine, 204 
Mucic acid, 156, 196 
Myristic acid, 206 
MjTistyl alcohol, 217 

N 

Naphtha quinaldine,/3-, 202 
Naphthaldehyde,/3-, 217 
Naphthalene, 228 

solubility of, 12 

-sulfonamide,a-, 213 

-sulfonamide,(3-, 213 

sulfonic acid,a-, 199 

sulfonic acid,/3-, (anhydr.), 199 

sulfonic acid,/3-, (trihydrate), 197 

-sulfonylchloride.a-, 239 

-sulfonylchloride,/3-, 239 



INDEX 



255 



Naphthalene tetrachloride, 231 
Naphthalic acid, 208 
Naphthoic acid,a-, 207 

acid,/3-, 207 

anhydride, 225 
Naphthol,a-, 210 

,/3-, 211 

-aldehyde, 1,4-, 211 

-3,6-disulfonic acid,2-, 199 

-6, 8-disulfonic acid,2-, 199 

-4-sulfonic acid,l-, 199 

-6-sulfonic acid,2-, 199 
Naphtho-nitrile,a-, 237 
,/3, 237 

-phthalein,a-, 209 

quinone,a-, 217 
,^-, 217 
Naphthyl-amine,a-, 202 

-amine,/3-, 203 

benzoate,/3-, 225 

ethyl ether,a-, 219 

ethyl ether,^-, 219, 220 

isoamyl ether,/3-, 219, 220 

methyl ether,a-, 219 

methyl ether,/3-, 220 

salicylate,/?-, 224 
Narcotine, 204 
Neutral equivalent, 138 
Nicotine, 95, 194 
Nicotinic acid, 204, 208 
Nitriles, 71 

Nitro groups, 71, 72, 145, 146 
Nitro-4-acetaminotoluene,3-, 233 

-acetanilide,m-, 234, 236 

-acetanilide,o-, 233, 235 

-acetanilide,p-, 234, 236 

-4-acetylaminotoluene,3-, 235 

-l-aminonaphthalene,2-, 203 

-4-aminotoluene,3-, 203, 233, 235 

-2-aminotoluene,4-, 203 

-2-aminotoluene,5-, 203 

-aniline,m-, 18, 203 

-aniline,o-, 18, 202, 234 

-aniline, p-, 18, 203 

-anisole,o-, 232 

-anisole,7>, 232 

benzal chloride,m-, 233 

-benzaldehyde,?^-, 233 



Nitro-benzaldehyde,c-, 232 
-benzaldehyde,p-, 233 
-benzamide,m-, 233, 235 
-benzamide,o-, 234, 236 
-benzamide,p-, 234, 236 
-benzanilide,™-, 233, 236 
-benzene, 232 
-benzoic acid,m-, 207 
-benzoic acid,o,- 207 
-benzoic acid,p-, 208 
-benzoic acids, 18 
-benzoyl chloride,??i-, 232 
-benzoyl chloride,p-, 233 
-benzyl alcohol, ??i-, 232 
-benzyl alcohol,o-, 233 
-benzyl alcohol, p-, 233 
-benzyl bromide, p-, 233 
-benzyl chloride,m-, 232 
-benzyl chloride,o-, 232 
-benzyl chloride, p-, 233 
-benzyl esters, p-, 6, 158 
-cinnamic acid,/«-, 208 
-cinnamic acid,o-, 208 
-cinnamic acid,p-, 208 
-cymene, 2, 232 
-dimethylaniline,m-, 202 
-dimethylaniline,p-, 203 
-diphenylamine,4-, 233 
-ethane, 212 
ethylacetanilide,p,- 233 
-X-ethylacetanilide.p-, 235 
-ethylaniline,m-, 233 
-guanidine, 212, 234 
-iodobenzene,o-, 232 
-iodobenzene,p-, 234 
-mesitylene, 232 
-methane, 194, 212 
-methylacetanilide,p-, 233 
-methylaniline,p-, 233 
-l-methylcyclohexane,l-, 232, 233 
-naphthalene,Q:-, 233 
-naphthalene,/?-, 233 
-phenetole,o-, 232 
-phenetole,p-, 233 
-phenol, m-, 210 
-phenol,o-, 210 
-phenol, p-, 210 
-phenols, 18 



256 



INDEX 



Nitro-phenyl acetonitrile,p-, 233 

-phenylacetic acid,p-, 207 

-phenylhydrazine,p-, 205 

-propane,n-, 212 

-quinaldine,6-, 204 

-quinoline,6-, 203 

-toluene,m-, 232 

-toluene, 0-, 232 

-toluene, P-, 232 

-o-toluidine,3-, 203 

-o-toluidine,6-, 203 

-p-toluidine,2-, 202 

-p-toluidine,3-, 203 

-urea, 212 

-TO-xylene,4-, 232 

-p-xylene,2-, 232 
Nitrogen compounds, 161 
Nitroso-benzene, 238 

-diethylaniline,p-, 202 

-dimethylaniline,p-, 202 

-diphenylamine,p-, 212, 238 

group, 71, 72 

-methylaminobenzoate,/^-, 203 

-methylaniline,/)-, 203 

-naphthol,l,4-, 211 

-«-naphthol,/3-, 211, 212 

-^-naphthol,a-, 210, 212 

-phenol, P-, 211, 212 
Nonanedicarboxylic acid, 206 

O 

Octane,n-, 227 

Octyl acetate, sec-, 222 

alcohol, 24, 215 

-amine, n-, 200 
Oleic acid, 206 
Orcinol, 192, 193 
Orthoform, 203 
Osazones, 71, 84, 85, 144, 155 
Ose group, 82 
Oxalic acid, 196 
Oxalyl chloride, 191 
Oxamide, 236 
Oxanilic acid, 207 
Oxanilide, 236 
Oxidation, permanganate, 33 

side-chains, 152, 154, 165 
Oximes, 71, 153 



Palmitic acid, 206 
Papaverine, 203 
Paraloain, 198 
Para-n-butyraldehyde, 215 
Paraldehyde, 190, 191, 215, 216, 

218 
Pentachloroethane, 229 
Pentaerythrite, 197 
Pentane, 227 
Pentoses, 86 
Peptides, 89 
Peracetic acid, 193 
Petroleum ether, 227 
Phenacetin, 235 
Phenanthraquinone, 102, 218 
Phenanthrene, 228 
Phenetidine,o-, 200 

,p-, 200 
Phenetole, 219 
Phenetyl urea,p-, 236 
Phenol, 192, 210 

-phthalein, 211 

-sulfonephthalein, 213 

sulfonic acid,p-, 199 
Phenols, 55, 57, 136, 159 
Phenoxyacetic acid, 193, 206 
Phenyl-acetamide,a-, 236 

-acetanilide,a-, 235 

acetate, 222 

-acetic acid, 206 

acetonitrile, 237 

acetyl chloride, 225 

-alanine,^//-, 204, 208 

-aminoacetic iicid,dl-, 204, 208 

benzenesulfonate, 239 

benzoate, 224 

carbamide, 235 

cinchoninic acid, 208 

cinnamate, 224 

disulfide, 239 

-ethyl alcohol,/3-, 216 

-ethyl barbituric acid, 212 

-glycine, 203, 207 

-hydrazine, 205 

-hydrazine test, 142, 143, 156 

hydrazones, 44, 153, 156, 171 



INDEX 



257 



Phenyl-hydroxylamine, 195 

isocyanate, 236, 237 

isocyanate test, 50 

isothiocyanate, 239 

-3-methyl pyrazolon-5,1-, 238 

-morpholine,4-, 202 

-a-naphthylamine,N-, 234 

-nitromethane, 212 

phthalate, 224 

propionate, 222, 224 

propiolic acid, 207 

-propyl alcohol, 216 

salicylate, 210 

sulfoxide, 239 

thiocarbamide, 240 

thiocyanate, 239 

-thiohydantoic acid, 213 

o-toluenesulfonate, 239 

p-toluenesulfonate, 239 

p-tolyl ketone, 217 

urethane,N-, 234 
Phenylenediamine,TO-, 194, 198, 202 

,0-, 194, 198, 203 

,p-, 194, 198, 203 
Phloroglucinol, 193, 211 
Phorone, 215, 217 
Phthalamide, 236 
Phthalanil, 236 
Phthaldehyde,o-, 217 
Phthalein test, 137 
Phthalic acid,o-, 208 

acids, 18 

anhydride, 207, 225 

anhydride test, 51, 62, 152, 174 
Phthalide, 224 
Phthalimide, 212 
Phthalimides, 164 
Phthalyl chloride, 225 
Physical constants. 111 

properties and structure, 8 
Picoline,a-, 194 
Picolinic acid, 203, 207 
Picramide, 236 
Picrates, 166 
Picric acid, 211 
Picryl chloride, 233 
Pimelic acid, 193, 206 
Pinacoline, 215 



Pinacone, 190, 191 

hydrate, 191 
Pinene, 226 

hydrochloride, 231 
Piperazine, 194, 198 

hydrate, 197 
Piperic acid, 208 
Piperidine, 193 
Piperine, 235 
Piperonal, 217 
Piperylhydrazine, 194 
Poly-glycolide, 225 

-hydroxy alcohols, 28 

-oxymethylene, 197, 218 

-substitution, 27, 99 
Populin, 218 
Procaine base, 202 
Propiolic acid, 192 
Propion-aldehyde, 189 

-amide, 195, 198 

-anilide, 235 
Propionic acid, 6, 192 

anhydride, 192 
Propionitrile, 194 
Propionyl chloride, 191 
Propiophenone, 216 
Propyl acetate,»-, 189, 220 

alcohol, 24, 50 

alcohol,n-, 189 

-aniine,n-, 193 

-aniline,^-, 200 

benzene, 227 

benzoate, n-, 222 

bromide, n-, 228 

n-butyrate,n-, 221 

carbamate, n-, 195 

carbonate, 7t-, 221 

chloride, n-, 228 

chlorocarbonate,n-, 220 

formate,?!-, 189 

iodide,n-, 229 

nitrate, n-, 237 

nitrite,?!-, 237 

oxalate,/!-, 222 

propionate, n-, 220 

red, 207 

salicylate, n-, 209 

succinate,/!-, 223 



258 



INDEX 



Propylene bromide, 229 

chloride, 229 

glycol, 196 
Proteins, 90 
Protocatcchuic acid, 208 

aldehyde, 193, 211 
Prussian blue, 123 
Pseudo-cumene, 227 

-cumenol, 210 

-cumidine, 202 

-ionone, 216 
Purines, 93 
Pyridine, 194 
Pyrimidines, 93 
Pyrogallol, 193 

triacetate, 225 
Pyromucic acid, 207 
Pyrrol, 237 
Pyruvic acid, 192 

Q 

Quercite,Z-, 197 
Quinaldine, 211 
Quinhy drone, 201 
Quinidine, dextxo, 20 '\ 
Quinine, 204 
Quinoline, 200 
Quinolinic acid, 204, 208 
Quinone {see Benzoquinone) 

R 

Raffinose, 197 
Reaction solvents, 9, 19 
Reactive methylene, 43 
Reducing agents, 69 
Reduction test, 145 
Reference books, 7, 105, 175 
Resorcinol, 193 

diacetate, 223 

monoacetate, 209 

-monomethyl ether, 209 
Resorcinyl dimethyl ether, 219 
Rhamnose, 197 
Rhodinol, 216 
Rota classification, 97 
Rules of solubility, 9 

of substitution, 37 



S 
Saccharin, 213 
Saccharose, 197 
Safrole, 219, 226 
Sahcin, 197, 218 
Salicyl-aldehyde, 209 

-amide, 211 
Salicylic acid, 207 
Santonin, 225 

Saponification equivalent, 140^^-' 
Sebacic acid, 207 
Semicarbazones, 71, 153 
Serine, 87 

Silver nitrate tests, 46, 142 
Sodium bisulfite test, 45, 141 

decomposition, 122 
Solubility prediction, 8, 131 

reagents, 126 

rules of, 9 

tabl% 23, 24 {see rear cover) 

tests, 126 
Solvents, 9 
Specific gravity, 120 
Starches, 87 
Stearic acid, 206 
Stilbene, 226, 228 
Strychnine, 204 
Styrene, 226 
Suberic acid, 207 
Substitution rules, 37 
Succinamide, 236 
Succinanil, 236 
Succinanilide, 236 
Succininc acid, 193, 196 

anhydride, 225 
Succinimide, 195, 198 
Succinonitrile, 195, 197, 237 
Succinyl chloride, 192 
Sulfanilic acid, 213 
Sulfanihde, 213 
Sulfides, 76 

Sulfite addition products, 45, 141 
Sulfoacetic acid, 199 
Sulfobenzoic acid, 199 
Sulfonal, 240 
Sulfonation, 36, 134 
Sulfonephthaleins, 213 
Sulfones, 77 



INDEX 



259 



Sulfonic acids, 78, 134 
Sulfosalicylic acid,l,2,5-, 199 
Sulfoxides, 77 
Sulfur coinpounds, 75 
Sulfuric acid test, 30, 126 
Superposition, method of, 2 
Sylvestrene, 226 



Tannic acid, 208 
Tartaric acid,ci-, 196 
,dl-, 196 
,i-, 196 
Tartaric acids, 17 
Terebene, 226 
Terephthaldehyde, 217 
Terephthalic acid, 209 
Terpin, 217 

hydrate, 217 
Terpineol, 216, 217 
Tertiary alcohols, 50 

amines, 65 
Tetra-bromobenzene, 1,2,4,5-, 231 

-bromo-o-cresol, 211 

-bromoethane,-s-, 230 

-chloroethane,s-, 229 

-chlorethylene, 229 

-chlorophthalic acid, 208 

-ethyl ammonium hydrate, 198 

-hydroquinoline, 201 

-methyl ammonium hydrate, 198 

-methyl dibromoethane,s-, 231 

-methyl p-phenylenediamine, 202 

-methyldiaminobenzophenone, 204 

-methyldiaminodiphenylmethane, 
202 

-nitromethane, 232 
Theobromine, 93, 212 
Theophylline, 93, 212 
Thio-acetic acid, 195 

-barbituric acid, 213 

-benzamide, 213 

-benzoic acid, 213 

-carbanilide, 240 

-cresol,?H-, 213 

-cresol,o-, 213 

-cresol,p-, 213 



Thio-naphthol,/3-, 213 
-phene, 238 
-phenol, 213 

-phthalic anhydride, 240 
-salicylic acid, 213 
-urea, 199 

Thiols, 76 

Thymol, 210 
-phthalein, 211 
-sulfonephthalein, 213 

Thymyl acetate, 223 
benzoate, 224 
methyl ether, 219 

Tolidine,o-, 203 

Toluamide,p-, 236 

Toluene, 227 

-sulfinic acid,p-, 213 
-sulfonamide,o-, 213 
-sulfonamide, p-, 213 
-sulfonic acid,/;-, 199 
-sulfonyl chloride,o-, 239 
-sulfonyl chloride,/)-, 239 
-sulfonylaniline, p-, 213 
-sulfonylethylaniline,p-, 239 
-sulfonyl-p-toluidine,p-, 213 

Toluhydroquinone, 193 

Toluic acid,?n-, 206 
acid,o-, 206 
acid,p-, 207 
acids, 18 

Toluidides, 157 

,P-, 6 
Toluidine,»2-, 200 

,0-, 200 

,p-,202 
ToluonitrLle,m-, 237 

,0-, 237 

,p-, 237 
Toluquinone, 217 
Toluylaldehyde,m-, 215 

,0-, 216 
Toluylhydrazine,/)-, 205 
Triacetin, 190, 223 
Triacetoneamine, 198 
Triallylamine, 200 
Tribenzylamine, 203 
Tribromo-aniline,s-, 235 

-anisole,s-, 220 



260 



INDEX 



Tribromo-/cr/-butyl alcohol, 218 

-phenetole,s-, 220 

-phenol, S-, 210 
Tri-M-butyl carbinol, 216 
Tri-n-butylamine, 200 
Tributyrin, 223 
Trichloro-acetic acid, 192 

-aniUne,s-, 202, 234 

-anisole,s-, 220 

-tert-butyl alcohol, 217 

-ethane, 1,1,1-, 229 

-ethane, 1,2,2-, 229 

-ethylene, 229 

-lactic acid, 193 

-lactonitrile, 195 

-phenetole,s-, 220 

-phenol,s-, 210 
Triethyl-amine, 200 

carbinol, 215 

citrate, 223 
Trimethylamine, 193 
Trimethylene bromide, 229 

bromohydrin, 190 

chloride, 229 

chlorohydrin, 190 

cyanide, 197, 237 

glycol, 196 

glycol diacetate, 190 
Trimyristin, 224 
Trinitro-anisole,s-, 233 

-benzaldehyde,2,4,6-, 233 

-benzene,s-, 233 

-benzoic acid,2,4,6-, 208 

-phenetole,s-, 233 

-toluene, 212 

-toluene, S-, 233 
Trioleine, 223 
Trional, 239 
Tripalmitin, 224 
Triphenyl-amine, 235 

-carbinol, 218 

-chloromethane, 231 

-guanidine, a-, 203 

-methane, 228 

-phosphate, 224 
Tri-n-propylamine, 200 
Tristearine, 224 



a 



Trithio-acetaldehyde,a-, 239 

-acetaldehyde,/3-, 240 

-formaldehyde, 240 
Tryptophane, 87 
Tyrosine, 87, 204, 209 

U 

Undecanoic acid, 206 
Undecenoic acid, 206 
Unsaturated hydrocarbons, 31 
Unsaturation test, 133, 134, 170 
Urea, 92 
Ureides, 92 
Urethanes, 152 
Uric acid, 93, 212 



Valeraldehyde.n-, 215 
Valeric acid,?i-, 6, 206 
Valerolactone,7-, 190 
Vanillic acid, 208 
Vanillin, 210, 217 
Van Slyke method, 88 
Veratrine, 204 
Veratrole, 219, 220 
Victor Meyer method, 51 
Volatility constants, 57, 139 



Xanthine, 93 
Xanthone, 218 
Xylene, m-, 227 

,0-, 227 

,p-, 227, 228 
Xylenol, 1,2,4-, 210 

,1,3,2-, 210 

,1,3,4-, 209, 210 
Xylidine,l,2,4-, 202 
Xylose, 197 



Zeiss! method, 172 



DATE DUE 




Oemco, Ifc 



V. 



/ells bindery inc. 

Valtham, mass. 

FEB. 19o8 



QD271.K3 



3 9358 00011428 7 



•^^—•mt^rmmmrmmm^m 



-I 'T- 



271 
K5 



Karam, Oliver 

\ Qualitative organic analysis. 
Wiley, 1923. 



11428 



CHEM 




BLDG 




f